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-rw-r--r--Makefile.config.in1
-rw-r--r--configure.ac14
-rw-r--r--doc/manual/expressions/builtins.xml34
-rw-r--r--doc/manual/introduction/about-nix.xml6
-rw-r--r--nix.spec.in2
-rw-r--r--release-common.nix21
-rw-r--r--release.nix31
-rw-r--r--shell.nix8
-rw-r--r--src/libexpr/eval.cc2
-rw-r--r--src/libexpr/get-drvs.cc3
-rw-r--r--src/libexpr/primops.cc56
-rw-r--r--src/libexpr/primops/fetchgit.cc2
-rw-r--r--src/libstore/build.cc40
-rw-r--r--src/libstore/builtins.cc3
-rw-r--r--src/libstore/download.cc45
-rw-r--r--src/libstore/download.hh1
-rw-r--r--src/libstore/export-import.cc8
-rw-r--r--src/libstore/gc.cc2
-rw-r--r--src/libstore/globals.cc4
-rw-r--r--src/libstore/globals.hh3
-rw-r--r--src/libstore/http-binary-cache-store.cc2
-rw-r--r--src/libstore/local-store.cc10
-rw-r--r--src/libstore/local.mk2
-rw-r--r--src/libstore/nar-accessor.cc108
-rw-r--r--src/libstore/optimise-store.cc2
-rw-r--r--src/libstore/store-api.cc11
-rw-r--r--src/libstore/store-api.hh5
-rw-r--r--src/libutil/logging.cc13
-rw-r--r--src/libutil/logging.hh93
-rw-r--r--src/libutil/types.hh17
-rw-r--r--src/libutil/util.cc2
-rw-r--r--src/libutil/util.hh2
-rw-r--r--src/linenoise/LICENSE25
-rw-r--r--src/linenoise/linenoise.c1199
-rw-r--r--src/linenoise/linenoise.h73
-rwxr-xr-xsrc/nix-channel/nix-channel.cc1
-rw-r--r--src/nix-daemon/nix-daemon.cc9
-rw-r--r--src/nix-env/nix-env.cc2
-rw-r--r--src/nix-instantiate/nix-instantiate.cc2
-rw-r--r--src/nix/installables.cc6
-rw-r--r--src/nix/local.mk6
-rw-r--r--src/nix/ls.cc4
-rw-r--r--src/nix/main.cc1
-rw-r--r--src/nix/progress-bar.cc251
-rw-r--r--src/nix/repl.cc167
-rw-r--r--src/nix/sigs.cc6
-rw-r--r--src/nix/verify.cc12
-rw-r--r--tests/lang/eval-okay-regex-match.nix3
-rw-r--r--tests/local.mk3
-rw-r--r--tests/nar-index.nix23
-rw-r--r--tests/nar-index.sh23
51 files changed, 1970 insertions, 399 deletions
diff --git a/Makefile.config.in b/Makefile.config.in
index 3cae30d487d7..45a70cd6dd1a 100644
--- a/Makefile.config.in
+++ b/Makefile.config.in
@@ -28,6 +28,7 @@ localstatedir = @localstatedir@
 mandir = @mandir@
 pkglibdir = $(libdir)/$(PACKAGE_NAME)
 prefix = @prefix@
+sandbox_shell = @sandbox_shell@
 storedir = @storedir@
 sysconfdir = @sysconfdir@
 doc_generate = @doc_generate@
diff --git a/configure.ac b/configure.ac
index ac37456ae5fe..24a95ce56f3b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -196,14 +196,6 @@ if test "$gc" = yes; then
 fi
 
 
-# Check for readline, needed by "nix repl".
-AX_LIB_READLINE
-if test "$ax_cv_lib_readline" != "no"; then
-  have_readline=1
-fi
-AC_SUBST(HAVE_READLINE, [$have_readline])
-
-
 AC_ARG_ENABLE(init-state, AC_HELP_STRING([--disable-init-state],
   [do not initialise DB etc. in `make install']),
   init_state=$enableval, init_state=yes)
@@ -248,6 +240,12 @@ fi
 AC_SUBST(tarFlags)
 
 
+AC_ARG_WITH(sandbox-shell, AC_HELP_STRING([--with-sandbox-shell=PATH],
+  [path of a statically-linked shell to use as /bin/sh in sandboxes]),
+  sandbox_shell=$withval)
+AC_SUBST(sandbox_shell)
+
+
 # Expand all variables in config.status.
 test "$prefix" = NONE && prefix=$ac_default_prefix
 test "$exec_prefix" = NONE && exec_prefix='${prefix}'
diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml
index 163153380ce4..f46a93ae0d5d 100644
--- a/doc/manual/expressions/builtins.xml
+++ b/doc/manual/expressions/builtins.xml
@@ -65,7 +65,7 @@ available as <function>builtins.derivation</function>.</para>
   <replaceable>set</replaceable></term>
 
     <listitem><para>Return the names of the attributes in the set
-    <replaceable>set</replaceable> in alphabetically sorted list.  For instance,
+    <replaceable>set</replaceable> in an alphabetically sorted list.  For instance,
     <literal>builtins.attrNames { y = 1; x = "foo"; }</literal>
     evaluates to <literal>[ "x" "y" ]</literal>.</para></listitem>
 
@@ -213,10 +213,11 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
   <varlistentry><term><function>builtins.match</function>
   <replaceable>regex</replaceable> <replaceable>str</replaceable></term>
 
-  <listitem><para>Returns a list if
-    <replaceable>regex</replaceable> matches
-    <replaceable>str</replaceable> precisely, otherwise returns <literal>null</literal>.
-    Each item in the list is a regex group.
+  <listitem><para>Returns a list if the <link
+  xlink:href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04">extended
+  POSIX regular expression</link> <replaceable>regex</replaceable>
+  matches <replaceable>str</replaceable> precisely, otherwise returns
+  <literal>null</literal>.  Each item in the list is a regex group.
 
 <programlisting>
 builtins.match "ab" "abc"
@@ -236,6 +237,11 @@ builtins.match "a(b)(c)" "abc"
 
 Evaluates to <literal>[ "b" "c" ]</literal>.
 
+<programlisting>
+builtins.match "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  FOO   "
+</programlisting>
+
+Evaluates to <literal>[ "foo" ]</literal>.
 
   </para></listitem>
   </varlistentry>
@@ -292,6 +298,24 @@ with import (fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixo
 stdenv.mkDerivation { … }
 </programlisting>
 
+    Note that when obtaining the hash with <varname>nix-prefetch-url
+    </varname> the option <varname>--unpack</varname> is required.
+    </para> 
+      
+    <para>This function can also verify the contents against a hash. 
+    In that case, the function takes a set instead of a URL. The set 
+    requires the attribute <varname>url</varname> and the attribute
+    <varname>sha256</varname>, e.g.
+      
+<programlisting>
+with import (fetchTarball {
+  url = https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz;
+  sha256 = "1jppksrfvbk5ypiqdz4cddxdl8z6zyzdb2srq8fcffr327ld5jj2";
+}) {};
+
+stdenv.mkDerivation { … }
+</programlisting>
+      
     </para>
 
     <para>This function is not available if <link
diff --git a/doc/manual/introduction/about-nix.xml b/doc/manual/introduction/about-nix.xml
index e6dfb7a5a565..be065da3eb2d 100644
--- a/doc/manual/introduction/about-nix.xml
+++ b/doc/manual/introduction/about-nix.xml
@@ -261,6 +261,12 @@ xlink:href="http://nixos.org/">NixOS homepage</link>.</para>
 xlink:href="http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html">GNU
 LGPLv2.1 or (at your option) any later version</link>.</para>
 
+<para>Nix uses the <link
+xlink:href="https://github.com/antirez/linenoise">linenoise
+library</link>, which has the following license:</para>
+
+<programlisting><xi:include href="../../../src/linenoise/LICENSE" parse="text" /></programlisting>
+
 </simplesect>
 
 
diff --git a/nix.spec.in b/nix.spec.in
index 3ba2dfc94b41..390893d64dc2 100644
--- a/nix.spec.in
+++ b/nix.spec.in
@@ -20,11 +20,9 @@ Requires: curl
 Requires: bzip2
 Requires: gzip
 Requires: xz
-Requires: readline
 BuildRequires: bzip2-devel
 BuildRequires: sqlite-devel
 BuildRequires: libcurl-devel
-BuildRequires: readline-devel
 
 # Hack to make that shitty RPM scanning hack shut up.
 Provides: perl(Nix::SSH)
diff --git a/release-common.nix b/release-common.nix
new file mode 100644
index 000000000000..8047c75bdb74
--- /dev/null
+++ b/release-common.nix
@@ -0,0 +1,21 @@
+{ pkgs }:
+
+rec {
+  sh = pkgs.busybox.override {
+    useMusl = true;
+    enableStatic = true;
+    enableMinimal = true;
+    extraConfig = ''
+      CONFIG_ASH y
+      CONFIG_ASH_BUILTIN_ECHO y
+      CONFIG_ASH_BUILTIN_TEST y
+      CONFIG_ASH_OPTIMIZE_FOR_SIZE y
+    '';
+  };
+
+  configureFlags =
+    [ "--disable-init-state"
+      "--enable-gc"
+      "--with-sandbox-shell=${sh}/bin/busybox"
+    ];
+}
diff --git a/release.nix b/release.nix
index fa2fde4f609b..f1a553d01cc6 100644
--- a/release.nix
+++ b/release.nix
@@ -66,6 +66,8 @@ let
 
       with import <nixpkgs> { inherit system; };
 
+      with import ./release-common.nix { inherit pkgs; };
+
       releaseTools.nixBuild {
         name = "nix";
         src = tarball;
@@ -73,7 +75,7 @@ let
         buildInputs =
           [ curl
             bzip2 xz brotli
-            openssl pkgconfig sqlite boehmgc readline
+            openssl pkgconfig sqlite boehmgc
 
           ]
           ++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium
@@ -83,11 +85,8 @@ let
               customMemoryManagement = false;
             });
 
-        configureFlags = ''
-          --disable-init-state
-          --enable-gc
-          --sysconfdir=/etc
-        '';
+        configureFlags = configureFlags ++
+          [ "--sysconfdir=/etc" ];
 
         enableParallelBuilding = true;
 
@@ -198,15 +197,15 @@ let
     rpm_fedora25x86_64 = makeRPM_x86_64 (diskImageFunsFun: diskImageFunsFun.fedora25x86_64) [ "libsodium-devel" ];
 
 
-    deb_debian8i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.debian8i386) [ "libsodium-dev" ] [ "libsodium13" "libreadline6" ];
-    deb_debian8x86_64 = makeDeb_x86_64 (diskImageFunsFun: diskImageFunsFun.debian8x86_64) [ "libsodium-dev" ] [ "libsodium13" "libreadline6" ];
+    deb_debian8i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.debian8i386) [ "libsodium-dev" ] [ "libsodium13" ];
+    deb_debian8x86_64 = makeDeb_x86_64 (diskImageFunsFun: diskImageFunsFun.debian8x86_64) [ "libsodium-dev" ] [ "libsodium13" ];
 
-    deb_ubuntu1410i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1410i386) [] [ "libreadline6" ];
-    deb_ubuntu1410x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1410x86_64) [] [ "libreadline6" ];
-    deb_ubuntu1604i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1604i386) [ "libsodium-dev" ] [ "libsodium18" "libreadline6" ];
-    deb_ubuntu1604x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1604x86_64) [ "libsodium-dev" ] [ "libsodium18" "libreadline6" ];
-    deb_ubuntu1610i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1610i386) [ "libsodium-dev" ] [ "libsodium18" "libreadline7" ];
-    deb_ubuntu1610x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1610x86_64) [ "libsodium-dev" ] [ "libsodium18" "libreadline7" ];
+    deb_ubuntu1410i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1410i386) [] [];
+    deb_ubuntu1410x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1410x86_64) [] [];
+    deb_ubuntu1604i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1604i386) [ "libsodium-dev" ] [ "libsodium18" ];
+    deb_ubuntu1604x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1604x86_64) [ "libsodium-dev" ] [ "libsodium18" ];
+    deb_ubuntu1610i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1610i386) [ "libsodium-dev" ] [ "libsodium18" ];
+    deb_ubuntu1610x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1610x86_64) [ "libsodium-dev" ] [ "libsodium18" ];
 
 
     # System tests.
@@ -299,7 +298,7 @@ let
       src = jobs.tarball;
       diskImage = (diskImageFun vmTools.diskImageFuns)
         { extraPackages =
-            [ "sqlite" "sqlite-devel" "bzip2-devel" "emacs" "libcurl-devel" "openssl-devel" "xz-devel" "readline-devel" ]
+            [ "sqlite" "sqlite-devel" "bzip2-devel" "emacs" "libcurl-devel" "openssl-devel" "xz-devel" ]
             ++ extraPackages; };
       memSize = 1024;
       meta.schedulingPriority = 50;
@@ -321,7 +320,7 @@ let
       src = jobs.tarball;
       diskImage = (diskImageFun vmTools.diskImageFuns)
         { extraPackages =
-            [ "libsqlite3-dev" "libbz2-dev" "libcurl-dev" "libcurl3-nss" "libssl-dev" "liblzma-dev" "libreadline-dev" ]
+            [ "libsqlite3-dev" "libbz2-dev" "libcurl-dev" "libcurl3-nss" "libssl-dev" "liblzma-dev" ]
             ++ extraPackages; };
       memSize = 1024;
       meta.schedulingPriority = 50;
diff --git a/shell.nix b/shell.nix
index bbce68564b95..c4e2a20f8fa7 100644
--- a/shell.nix
+++ b/shell.nix
@@ -2,6 +2,8 @@
 
 with import <nixpkgs> {};
 
+with import ./release-common.nix { inherit pkgs; };
+
 (if useClang then clangStdenv else stdenv).mkDerivation {
   name = "nix";
 
@@ -16,17 +18,13 @@ with import <nixpkgs> {};
         customMemoryManagement = false;
       })
       autoreconfHook
-      readline
 
       # For nix-perl
       perl
       perlPackages.DBDSQLite
     ];
 
-  configureFlags =
-    [ "--disable-init-state"
-      "--enable-gc"
-    ];
+  inherit configureFlags;
 
   enableParallelBuilding = true;
 
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 5e1ae63c4824..0cdce602d7b2 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -642,7 +642,7 @@ void EvalState::evalFile(const Path & path, Value & v)
         return;
     }
 
-    Activity act(*logger, lvlTalkative, format("evaluating file ‘%1%’") % path2);
+    printTalkative("evaluating file ‘%1%’", path2);
     Expr * e = parseExprFromFile(checkSourcePath(path2));
     try {
         eval(e, v);
diff --git a/src/libexpr/get-drvs.cc b/src/libexpr/get-drvs.cc
index ae9fb0e5ec38..4200e8fd6757 100644
--- a/src/libexpr/get-drvs.cc
+++ b/src/libexpr/get-drvs.cc
@@ -289,7 +289,7 @@ static void getDerivations(EvalState & state, Value & vIn,
            bound to the attribute with the "lower" name should take
            precedence). */
         for (auto & i : v.attrs->lexicographicOrder()) {
-            Activity act(*logger, lvlDebug, format("evaluating attribute ‘%1%’") % i->name);
+            debug("evaluating attribute ‘%1%’", i->name);
             if (!std::regex_match(std::string(i->name), attrRegex))
                 continue;
             string pathPrefix2 = addToPath(pathPrefix, i->name);
@@ -310,7 +310,6 @@ static void getDerivations(EvalState & state, Value & vIn,
 
     else if (v.isList()) {
         for (unsigned int n = 0; n < v.listSize(); ++n) {
-            Activity act(*logger, lvlDebug, "evaluating list element");
             string pathPrefix2 = addToPath(pathPrefix, (format("%1%") % n).str());
             if (getDerivation(state, *v.listElems()[n], pathPrefix2, drvs, done, ignoreAssertionFailures))
                 getDerivations(state, *v.listElems()[n], pathPrefix2, autoArgs, drvs, done, ignoreAssertionFailures);
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 615cc8138433..99ffddaeb80c 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -127,7 +127,7 @@ static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args
                 env->values[displ++] = attr.value;
             }
 
-            Activity act(*logger, lvlTalkative, format("evaluating file ‘%1%’") % path);
+            printTalkative("evaluating file ‘%1%’", path);
             Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv);
 
             e->eval(state, *env, v);
@@ -326,8 +326,6 @@ typedef list<Value *> ValueList;
 
 static void prim_genericClosure(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    Activity act(*logger, lvlDebug, "finding dependencies");
-
     state.forceAttrs(*args[0], pos);
 
     /* Get the start set. */
@@ -499,8 +497,6 @@ void prim_valueSize(EvalState & state, const Pos & pos, Value * * args, Value &
    derivation. */
 static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    Activity act(*logger, lvlVomit, "evaluating derivation");
-
     state.forceAttrs(*args[0], pos);
 
     /* Figure out the name first (for stack backtraces). */
@@ -534,7 +530,8 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
     PathSet context;
 
-    string outputHash, outputHashAlgo;
+    std::experimental::optional<std::string> outputHash;
+    std::string outputHashAlgo;
     bool outputHashRecursive = false;
 
     StringSet outputs;
@@ -543,7 +540,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
     for (auto & i : args[0]->attrs->lexicographicOrder()) {
         if (i->name == state.sIgnoreNulls) continue;
         string key = i->name;
-        Activity act(*logger, lvlVomit, format("processing attribute ‘%1%’") % key);
+        vomit("processing attribute ‘%1%’", key);
 
         auto handleHashMode = [&](const std::string & s) {
             if (s == "recursive") outputHashRecursive = true;
@@ -703,7 +700,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
         throw EvalError(format("derivation names are not allowed to end in ‘%1%’, at %2%")
             % drvExtension % posDrvName);
 
-    if (outputHash != "") {
+    if (outputHash) {
         /* Handle fixed-output derivations. */
         if (outputs.size() != 1 || *(outputs.begin()) != "out")
             throw Error(format("multiple outputs are not supported in fixed-output derivations, at %1%") % posDrvName);
@@ -711,13 +708,13 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
         HashType ht = parseHashType(outputHashAlgo);
         if (ht == htUnknown)
             throw EvalError(format("unknown hash algorithm ‘%1%’, at %2%") % outputHashAlgo % posDrvName);
-        Hash h = parseHash16or32(ht, outputHash);
+        Hash h = parseHash16or32(ht, *outputHash);
         outputHash = printHash(h);
         if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo;
 
         Path outPath = state.store->makeFixedOutputPath(outputHashRecursive, h, drvName);
         drv.env["out"] = outPath;
-        drv.outputs["out"] = DerivationOutput(outPath, outputHashAlgo, outputHash);
+        drv.outputs["out"] = DerivationOutput(outPath, outputHashAlgo, *outputHash);
     }
 
     else {
@@ -1712,26 +1709,33 @@ static void prim_hashString(EvalState & state, const Pos & pos, Value * * args,
    ‘null’ or a list containing substring matches. */
 static void prim_match(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    std::regex regex(state.forceStringNoCtx(*args[0], pos), std::regex::extended);
+    auto re = state.forceStringNoCtx(*args[0], pos);
 
-    PathSet context;
-    const std::string str = state.forceString(*args[1], context, pos);
+    try {
 
+        std::regex regex(re, std::regex::extended);
 
-    std::smatch match;
-    if (!std::regex_match(str, match, regex)) {
-        mkNull(v);
-        return;
-    }
+        PathSet context;
+        const std::string str = state.forceString(*args[1], context, pos);
 
-    // the first match is the whole string
-    const size_t len = match.size() - 1;
-    state.mkList(v, len);
-    for (size_t i = 0; i < len; ++i) {
-        if (!match[i+1].matched)
-            mkNull(*(v.listElems()[i] = state.allocValue()));
-        else
-            mkString(*(v.listElems()[i] = state.allocValue()), match[i + 1].str().c_str());
+        std::smatch match;
+        if (!std::regex_match(str, match, regex)) {
+            mkNull(v);
+            return;
+        }
+
+        // the first match is the whole string
+        const size_t len = match.size() - 1;
+        state.mkList(v, len);
+        for (size_t i = 0; i < len; ++i) {
+            if (!match[i+1].matched)
+                mkNull(*(v.listElems()[i] = state.allocValue()));
+            else
+                mkString(*(v.listElems()[i] = state.allocValue()), match[i + 1].str().c_str());
+        }
+
+    } catch (std::regex_error &) {
+        throw EvalError("invalid regular expression ‘%s’, at %s", re, pos);
     }
 }
 
diff --git a/src/libexpr/primops/fetchgit.cc b/src/libexpr/primops/fetchgit.cc
index 09e2c077baba..3e4ece2cffdc 100644
--- a/src/libexpr/primops/fetchgit.cc
+++ b/src/libexpr/primops/fetchgit.cc
@@ -17,7 +17,7 @@ Path exportGit(ref<Store> store, const std::string & uri, const std::string & re
         runProgram("git", true, { "init", "--bare", cacheDir });
     }
 
-    Activity act(*logger, lvlInfo, format("fetching Git repository ‘%s’") % uri);
+    //Activity act(*logger, lvlInfo, format("fetching Git repository ‘%s’") % uri);
 
     std::string localRef = "pid-" + std::to_string(getpid());
     Path localRefFile = cacheDir + "/refs/heads/" + localRef;
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 270500d81c90..44cae3431fc2 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -120,6 +120,8 @@ protected:
     /* Whether the goal is finished. */
     ExitCode exitCode;
 
+    Activity act;
+
     Goal(Worker & worker) : worker(worker)
     {
         nrFailed = nrNoSubstituters = nrIncompleteClosure = 0;
@@ -168,7 +170,8 @@ public:
     virtual string key() = 0;
 
 protected:
-    void amDone(ExitCode result);
+
+    virtual void amDone(ExitCode result);
 };
 
 
@@ -902,6 +905,12 @@ private:
 
     void repairClosure();
 
+    void amDone(ExitCode result)
+    {
+        logger->event(evBuildFinished, act, result == ecSuccess);
+        Goal::amDone(result);
+    }
+
     void done(BuildResult::Status status, const string & msg = "");
 };
 
@@ -920,6 +929,8 @@ DerivationGoal::DerivationGoal(const Path & drvPath, const StringSet & wantedOut
     state = &DerivationGoal::getDerivation;
     name = (format("building of ‘%1%’") % drvPath).str();
     trace("created");
+
+    logger->event(evBuildCreated, act, drvPath);
 }
 
 
@@ -935,6 +946,8 @@ DerivationGoal::DerivationGoal(const Path & drvPath, const BasicDerivation & drv
     name = (format("building of %1%") % showPaths(drv.outputPaths())).str();
     trace("created");
 
+    logger->event(evBuildCreated, act, drvPath);
+
     /* Prevent the .chroot directory from being
        garbage-collected. (See isActiveTempFile() in gc.cc.) */
     worker.store.addTempRoot(drvPath);
@@ -1066,12 +1079,8 @@ void DerivationGoal::haveDerivation()
 
     /* Reject doing a hash build of anything other than a fixed-output
        derivation. */
-    if (buildMode == bmHash) {
-        if (drv->outputs.size() != 1 ||
-            drv->outputs.find("out") == drv->outputs.end() ||
-            drv->outputs["out"].hashAlgo == "")
-            throw Error(format("cannot do a hash build of non-fixed-output derivation ‘%1%’") % drvPath);
-    }
+    if (buildMode == bmHash && !drv->isFixedOutput())
+        throw Error("cannot do a hash build of non-fixed-output derivation ‘%1%’", drvPath);
 
     /* We are first going to try to create the invalid output paths
        through substitutes.  If that doesn't work, we'll build
@@ -1774,6 +1783,7 @@ void DerivationGoal::startBuilder()
             try {
                 if (worker.store.isInStore(i.second.source))
                     worker.store.computeFSClosure(worker.store.toStorePath(i.second.source), closure);
+            } catch (InvalidPath & e) {
             } catch (Error & e) {
                 throw Error(format("while processing ‘build-sandbox-paths’: %s") % e.what());
             }
@@ -2115,6 +2125,8 @@ void DerivationGoal::startBuilder()
         }
         debug(msg);
     }
+
+    logger->event(evBuildStarted, act);
 }
 
 
@@ -2860,7 +2872,7 @@ void DerivationGoal::registerOutputs()
            contained in it.  Compute the SHA-256 NAR hash at the same
            time.  The hash is stored in the database so that we can
            verify later on whether nobody has messed with the store. */
-        Activity act(*logger, lvlTalkative, format("scanning for references inside ‘%1%’") % path);
+        debug("scanning for references inside ‘%1%’", path);
         HashResult hash;
         PathSet references = scanForReferences(actualPath, allPaths, hash);
 
@@ -3133,6 +3145,7 @@ void DerivationGoal::flushLine()
         logTail.push_back(currentLogLine);
         if (logTail.size() > settings.logLines) logTail.pop_front();
     }
+    logger->event(evBuildOutput, act, currentLogLine);
     currentLogLine = "";
     currentLogLinePos = 0;
 }
@@ -3247,6 +3260,12 @@ public:
     void handleEOF(int fd);
 
     Path getStorePath() { return storePath; }
+
+    void amDone(ExitCode result)
+    {
+        logger->event(evSubstitutionFinished, act, result == ecSuccess);
+        Goal::amDone(result);
+    }
 };
 
 
@@ -3259,6 +3278,7 @@ SubstitutionGoal::SubstitutionGoal(const Path & storePath, Worker & worker, bool
     state = &SubstitutionGoal::init;
     name = (format("substitution of ‘%1%’") % storePath).str();
     trace("created");
+    logger->event(evSubstitutionCreated, act, storePath);
 }
 
 
@@ -3394,6 +3414,8 @@ void SubstitutionGoal::tryToRun()
 
     printInfo(format("fetching path ‘%1%’...") % storePath);
 
+    logger->event(evSubstitutionStarted, act);
+
     outPipe.create();
 
     promise = std::promise<void>();
@@ -3640,7 +3662,7 @@ void Worker::run(const Goals & _topGoals)
 {
     for (auto & i : _topGoals) topGoals.insert(i);
 
-    Activity act(*logger, lvlDebug, "entered goal loop");
+    debug("entered goal loop");
 
     while (1) {
 
diff --git a/src/libstore/builtins.cc b/src/libstore/builtins.cc
index c5dbd57f8bc6..8a5cf3327d44 100644
--- a/src/libstore/builtins.cc
+++ b/src/libstore/builtins.cc
@@ -28,9 +28,6 @@ void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData)
         DownloadRequest request(url);
         request.verifyTLS = false;
 
-        /* Show a progress indicator, even though stderr is not a tty. */
-        request.showProgress = DownloadRequest::yes;
-
         /* Note: have to use a fresh downloader here because we're in
            a forked process. */
         auto data = makeDownloader()->download(request);
diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index 4d502219ed86..63e498f0603a 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -63,6 +63,7 @@ struct CurlDownloader : public Downloader
         CurlDownloader & downloader;
         DownloadRequest request;
         DownloadResult result;
+        Activity act;
         bool done = false; // whether either the success or failure function has been called
         std::function<void(const DownloadResult &)> success;
         std::function<void(std::exception_ptr exc)> failure;
@@ -70,10 +71,6 @@ struct CurlDownloader : public Downloader
         bool active = false; // whether the handle has been added to the multi object
         std::string status;
 
-        bool showProgress = false;
-        double prevProgressTime{0}, startTime{0};
-        unsigned int moveBack{1};
-
         unsigned int attempt = 0;
 
         /* Don't start this download until the specified time point
@@ -87,12 +84,10 @@ struct CurlDownloader : public Downloader
         DownloadItem(CurlDownloader & downloader, const DownloadRequest & request)
             : downloader(downloader), request(request)
         {
-            showProgress =
-                request.showProgress == DownloadRequest::yes ||
-                (request.showProgress == DownloadRequest::automatic && isatty(STDERR_FILENO));
-
             if (!request.expectedETag.empty())
                 requestHeaders = curl_slist_append(requestHeaders, ("If-None-Match: " + request.expectedETag).c_str());
+
+            logger->event(evDownloadCreated, act, request.uri);
         }
 
         ~DownloadItem()
@@ -109,6 +104,7 @@ struct CurlDownloader : public Downloader
             } catch (...) {
                 ignoreException();
             }
+            logger->event(evDownloadDestroyed, act);
         }
 
         template<class T>
@@ -171,19 +167,7 @@ struct CurlDownloader : public Downloader
 
         int progressCallback(double dltotal, double dlnow)
         {
-            if (showProgress) {
-                double now = getTime();
-                if (prevProgressTime <= now - 1) {
-                    string s = (format(" [%1$.0f/%2$.0f KiB, %3$.1f KiB/s]")
-                        % (dlnow / 1024.0)
-                        % (dltotal / 1024.0)
-                        % (now == startTime ? 0 : dlnow / 1024.0 / (now - startTime))).str();
-                    std::cerr << "\e[" << moveBack << "D" << s;
-                    moveBack = s.size();
-                    std::cerr.flush();
-                    prevProgressTime = now;
-                }
-            }
+            logger->event(evDownloadProgress, act, dltotal, dlnow);
             return _isInterrupted;
         }
 
@@ -201,13 +185,6 @@ struct CurlDownloader : public Downloader
 
         void init()
         {
-            // FIXME: handle parallel downloads.
-            if (showProgress) {
-                std::cerr << (format("downloading ‘%1%’... ") % request.uri);
-                std::cerr.flush();
-                startTime = getTime();
-            }
-
             if (!req) req = curl_easy_init();
 
             curl_easy_reset(req);
@@ -220,7 +197,9 @@ struct CurlDownloader : public Downloader
             curl_easy_setopt(req, CURLOPT_URL, request.uri.c_str());
             curl_easy_setopt(req, CURLOPT_FOLLOWLOCATION, 1L);
             curl_easy_setopt(req, CURLOPT_NOSIGNAL, 1);
-            curl_easy_setopt(req, CURLOPT_USERAGENT, ("curl/" LIBCURL_VERSION " Nix/" + nixVersion).c_str());
+            curl_easy_setopt(req, CURLOPT_USERAGENT,
+                ("curl/" LIBCURL_VERSION " Nix/" + nixVersion +
+                    (settings.userAgentSuffix != "" ? " " + settings.userAgentSuffix.get() : "")).c_str());
             #if LIBCURL_VERSION_NUM >= 0x072b00
             curl_easy_setopt(req, CURLOPT_PIPEWAIT, 1);
             #endif
@@ -261,10 +240,6 @@ struct CurlDownloader : public Downloader
 
         void finish(CURLcode code)
         {
-            if (showProgress)
-                //std::cerr << "\e[" << moveBack << "D\e[K\n";
-                std::cerr << "\n";
-
             long httpStatus = 0;
             curl_easy_getinfo(req, CURLINFO_RESPONSE_CODE, &httpStatus);
 
@@ -290,6 +265,7 @@ struct CurlDownloader : public Downloader
                 try {
                     result.data = decodeContent(encoding, ref<std::string>(result.data));
                     callSuccess(success, failure, const_cast<const DownloadResult &>(result));
+                    logger->event(evDownloadSucceeded, act, result.data->size());
                 } catch (...) {
                     done = true;
                     callFailure(failure, std::current_exception());
@@ -652,6 +628,7 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
                 Hash hash = hashString(expectedHash ? expectedHash.type : htSHA256, *res.data);
                 info.path = store->makeFixedOutputPath(false, hash, name);
                 info.narHash = hashString(htSHA256, *sink.s);
+                info.narSize = sink.s->size();
                 info.ca = makeFixedOutputCA(false, hash);
                 store->addToStore(info, sink.s, false, true);
                 storePath = info.path;
@@ -689,7 +666,7 @@ Path Downloader::downloadCached(ref<Store> store, const string & url_, bool unpa
     }
 
     if (expectedStorePath != "" && storePath != expectedStorePath)
-        throw nix::Error(format("hash mismatch in file downloaded from ‘%s’") % url);
+        throw nix::Error("store path mismatch in file downloaded from ‘%s’", url);
 
     return storePath;
 }
diff --git a/src/libstore/download.hh b/src/libstore/download.hh
index 62f3860b9dae..7d8982d64c4c 100644
--- a/src/libstore/download.hh
+++ b/src/libstore/download.hh
@@ -13,7 +13,6 @@ struct DownloadRequest
     std::string uri;
     std::string expectedETag;
     bool verifyTLS = true;
-    enum { yes, no, automatic } showProgress = yes;
     bool head = false;
     size_t tries = 5;
     unsigned int baseRetryTimeMs = 250;
diff --git a/src/libstore/export-import.cc b/src/libstore/export-import.cc
index 2b8ab063e18e..6e8bc692cdff 100644
--- a/src/libstore/export-import.cc
+++ b/src/libstore/export-import.cc
@@ -30,13 +30,13 @@ void Store::exportPaths(const Paths & paths, Sink & sink)
     std::reverse(sorted.begin(), sorted.end());
 
     std::string doneLabel("paths exported");
-    logger->incExpected(doneLabel, sorted.size());
+    //logger->incExpected(doneLabel, sorted.size());
 
     for (auto & path : sorted) {
-        Activity act(*logger, lvlInfo, format("exporting path ‘%s’") % path);
+        //Activity act(*logger, lvlInfo, format("exporting path ‘%s’") % path);
         sink << 1;
         exportPath(path, sink);
-        logger->incProgress(doneLabel);
+        //logger->incProgress(doneLabel);
     }
 
     sink << 0;
@@ -81,7 +81,7 @@ Paths Store::importPaths(Source & source, std::shared_ptr<FSAccessor> accessor,
 
         info.path = readStorePath(*this, source);
 
-        Activity act(*logger, lvlInfo, format("importing path ‘%s’") % info.path);
+        //Activity act(*logger, lvlInfo, format("importing path ‘%s’") % info.path);
 
         info.references = readStorePaths<PathSet>(*this, source);
 
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index 3e7e42cbc969..3cdbb114a79d 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -615,7 +615,7 @@ void LocalStore::tryToDelete(GCState & state, const Path & path)
     auto realPath = realStoreDir + "/" + baseNameOf(path);
     if (realPath == linksDir || realPath == trashDir) return;
 
-    Activity act(*logger, lvlDebug, format("considering whether to delete ‘%1%’") % path);
+    //Activity act(*logger, lvlDebug, format("considering whether to delete ‘%1%’") % path);
 
     if (!isStorePath(path) || !isValidPath(path)) {
         /* A lock file belonging to a path that we're building right
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index 4bdbde989ab2..3dd2508a26d3 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -47,8 +47,8 @@ Settings::Settings()
     auto s = getEnv("NIX_REMOTE_SYSTEMS");
     if (s != "") builderFiles = tokenizeString<Strings>(s, ":");
 
-#if __linux__
-    sandboxPaths = tokenizeString<StringSet>("/bin/sh=" BASH_PATH);
+#if defined(__linux__) && defined(SANDBOX_SHELL)
+    sandboxPaths = tokenizeString<StringSet>("/bin/sh=" SANDBOX_SHELL);
 #endif
 
     allowedImpureHostPrefixes = tokenizeString<StringSet>(DEFAULT_ALLOWED_IMPURE_PREFIXES);
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 7295b0d30af0..af37ec61d7a1 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -318,6 +318,9 @@ public:
 
     Setting<unsigned long> connectTimeout{this, 0, "connect-timeout",
         "Timeout for connecting to servers during downloads. 0 means use curl's builtin default."};
+
+    Setting<std::string> userAgentSuffix{this, "", "user-agent-suffix",
+        "String appended to the user agent in HTTP requests."};
 };
 
 
diff --git a/src/libstore/http-binary-cache-store.cc b/src/libstore/http-binary-cache-store.cc
index 37a7d6ace142..cead81514ab4 100644
--- a/src/libstore/http-binary-cache-store.cc
+++ b/src/libstore/http-binary-cache-store.cc
@@ -50,7 +50,6 @@ protected:
     {
         try {
             DownloadRequest request(cacheUri + "/" + path);
-            request.showProgress = DownloadRequest::no;
             request.head = true;
             request.tries = 5;
             getDownloader()->download(request);
@@ -76,7 +75,6 @@ protected:
         std::function<void(std::exception_ptr exc)> failure) override
     {
         DownloadRequest request(cacheUri + "/" + path);
-        request.showProgress = DownloadRequest::no;
         request.tries = 8;
 
         getDownloader()->enqueueDownload(request,
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index c8e61126c1b8..207e8a40b6d3 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -919,8 +919,12 @@ void LocalStore::addToStore(const ValidPathInfo & info, const ref<std::string> &
 
     Hash h = hashString(htSHA256, *nar);
     if (h != info.narHash)
-        throw Error(format("hash mismatch importing path ‘%s’; expected hash ‘%s’, got ‘%s’") %
-            info.path % info.narHash.to_string() % h.to_string());
+        throw Error("hash mismatch importing path ‘%s’; expected hash ‘%s’, got ‘%s’",
+            info.path, info.narHash.to_string(), h.to_string());
+
+    if (nar->size() != info.narSize)
+        throw Error("szie mismatch importing path ‘%s’; expected %s, got %s",
+            info.path, info.narSize, nar->size());
 
     if (requireSigs && !dontCheckSigs && !info.checkSignatures(*this, publicKeys))
         throw Error("cannot add path ‘%s’ because it lacks a valid signature", info.path);
@@ -1006,7 +1010,6 @@ Path LocalStore::addToStoreFromDump(const string & dump, const string & name,
             info.path = dstPath;
             info.narHash = hash.first;
             info.narSize = hash.second;
-            info.ultimate = true;
             info.ca = makeFixedOutputCA(recursive, h);
             registerValidPath(info);
         }
@@ -1069,7 +1072,6 @@ Path LocalStore::addTextToStore(const string & name, const string & s,
             info.narHash = narHash;
             info.narSize = sink.s->size();
             info.references = references;
-            info.ultimate = true;
             info.ca = "text:" + hash.to_string();
             registerValidPath(info);
         }
diff --git a/src/libstore/local.mk b/src/libstore/local.mk
index 4da20330cf3f..e06002587f94 100644
--- a/src/libstore/local.mk
+++ b/src/libstore/local.mk
@@ -27,7 +27,7 @@ libstore_CXXFLAGS = \
  -DNIX_CONF_DIR=\"$(sysconfdir)/nix\" \
  -DNIX_LIBEXEC_DIR=\"$(libexecdir)\" \
  -DNIX_BIN_DIR=\"$(bindir)\" \
- -DBASH_PATH="\"$(bash)\"" \
+ -DSANDBOX_SHELL="\"$(sandbox_shell)\"" \
  -DLSOF=\"$(lsof)\"
 
 $(d)/local-store.cc: $(d)/schema.sql.hh
diff --git a/src/libstore/nar-accessor.cc b/src/libstore/nar-accessor.cc
index 4cb5de7449ea..82595e76a9b5 100644
--- a/src/libstore/nar-accessor.cc
+++ b/src/libstore/nar-accessor.cc
@@ -2,6 +2,8 @@
 #include "archive.hh"
 
 #include <map>
+#include <stack>
+#include <algorithm>
 
 namespace nix {
 
@@ -16,16 +18,16 @@ struct NarMember
     size_t start, size;
 
     std::string target;
+
+    /* If this is a directory, all the children of the directory. */
+    std::map<std::string, NarMember> children;
 };
 
 struct NarIndexer : ParseSink, StringSource
 {
-    // FIXME: should store this as a tree. Now we're vulnerable to
-    // O(nm) memory consumption (e.g. for x_0/.../x_n/{y_0..y_m}).
-    typedef std::map<Path, NarMember> Members;
-    Members members;
+    NarMember root;
+    std::stack<NarMember*> parents;
 
-    Path currentPath;
     std::string currentStart;
     bool isExec = false;
 
@@ -33,28 +35,45 @@ struct NarIndexer : ParseSink, StringSource
     {
     }
 
+    void createMember(const Path & path, NarMember member) {
+        size_t level = std::count(path.begin(), path.end(), '/');
+        while(parents.size() > level) {
+            parents.pop();
+        }
+
+        if(parents.empty()) {
+            root = std::move(member);
+            parents.push(&root);
+        } else {
+            if(parents.top()->type != FSAccessor::Type::tDirectory) {
+                throw Error(format("NAR file missing parent directory of path ‘%1%’") % path);
+            }
+            auto result = parents.top()->children.emplace(baseNameOf(path), std::move(member));
+            parents.push(&result.first->second);
+        }
+    }
+
     void createDirectory(const Path & path) override
     {
-        members.emplace(path,
-            NarMember{FSAccessor::Type::tDirectory, false, 0, 0});
+        createMember(path, {FSAccessor::Type::tDirectory, false, 0, 0 });
     }
 
     void createRegularFile(const Path & path) override
     {
-        currentPath = path;
+        createMember(path, {FSAccessor::Type::tRegular, false, 0, 0 });
     }
 
     void isExecutable() override
     {
-        isExec = true;
+        parents.top()->isExecutable = true;
     }
 
     void preallocateContents(unsigned long long size) override
     {
         currentStart = string(s, pos, 16);
         assert(size <= std::numeric_limits<size_t>::max());
-        members.emplace(currentPath,
-            NarMember{FSAccessor::Type::tRegular, isExec, pos, (size_t) size});
+        parents.top()->size = (size_t)size;
+        parents.top()->start = pos;
     }
 
     void receiveContents(unsigned char * data, unsigned int len) override
@@ -68,16 +87,42 @@ struct NarIndexer : ParseSink, StringSource
 
     void createSymlink(const Path & path, const string & target) override
     {
-        members.emplace(path,
+        createMember(path,
             NarMember{FSAccessor::Type::tSymlink, false, 0, 0, target});
     }
 
-    Members::iterator find(const Path & path)
+    NarMember* find(const Path & path)
     {
-        auto i = members.find(path);
-        if (i == members.end())
+        Path canon = path == "" ? "" : canonPath(path);
+        NarMember* current = &root;
+        auto end = path.end();
+        for(auto it = path.begin(); it != end; ) {
+            // because it != end, the remaining component is non-empty so we need
+            // a directory
+            if(current->type != FSAccessor::Type::tDirectory) return nullptr;
+
+            // skip slash (canonPath above ensures that this is always a slash)
+            assert(*it == '/');
+            it += 1;
+
+            // lookup current component
+            auto next = std::find(it, end, '/');
+            auto child = current->children.find(std::string(it, next));
+            if(child == current->children.end()) return nullptr;
+            current = &child->second;
+
+            it = next;
+        }
+
+        return current;
+    }
+
+    NarMember& at(const Path & path) {
+        auto result = find(path);
+        if(result == nullptr) {
             throw Error(format("NAR file does not contain path ‘%1%’") % path);
-        return i;
+        }
+        return *result;
     }
 };
 
@@ -93,44 +138,41 @@ struct NarAccessor : public FSAccessor
 
     Stat stat(const Path & path) override
     {
-        auto i = indexer.members.find(path);
-        if (i == indexer.members.end())
+        auto i = indexer.find(path);
+        if (i == nullptr)
             return {FSAccessor::Type::tMissing, 0, false};
-        return {i->second.type, i->second.size, i->second.isExecutable};
+        return {i->type, i->size, i->isExecutable};
     }
 
     StringSet readDirectory(const Path & path) override
     {
-        auto i = indexer.find(path);
+        auto i = indexer.at(path);
 
-        if (i->second.type != FSAccessor::Type::tDirectory)
+        if (i.type != FSAccessor::Type::tDirectory)
             throw Error(format("path ‘%1%’ inside NAR file is not a directory") % path);
 
-        ++i;
         StringSet res;
-        while (i != indexer.members.end() && isInDir(i->first, path)) {
-            // FIXME: really bad performance.
-            if (i->first.find('/', path.size() + 1) == std::string::npos)
-                res.insert(std::string(i->first, path.size() + 1));
-            ++i;
+        for(auto&& child : i.children) {
+            res.insert(child.first);
+
         }
         return res;
     }
 
     std::string readFile(const Path & path) override
     {
-        auto i = indexer.find(path);
-        if (i->second.type != FSAccessor::Type::tRegular)
+        auto i = indexer.at(path);
+        if (i.type != FSAccessor::Type::tRegular)
             throw Error(format("path ‘%1%’ inside NAR file is not a regular file") % path);
-        return std::string(*nar, i->second.start, i->second.size);
+        return std::string(*nar, i.start, i.size);
     }
 
     std::string readLink(const Path & path) override
     {
-        auto i = indexer.find(path);
-        if (i->second.type != FSAccessor::Type::tSymlink)
+        auto i = indexer.at(path);
+        if (i.type != FSAccessor::Type::tSymlink)
             throw Error(format("path ‘%1%’ inside NAR file is not a symlink") % path);
-        return i->second.target;
+        return i.target;
     }
 };
 
diff --git a/src/libstore/optimise-store.cc b/src/libstore/optimise-store.cc
index d354812e3da4..56167c4dfae8 100644
--- a/src/libstore/optimise-store.cc
+++ b/src/libstore/optimise-store.cc
@@ -240,7 +240,7 @@ void LocalStore::optimiseStore(OptimiseStats & stats)
     for (auto & i : paths) {
         addTempRoot(i);
         if (!isValidPath(i)) continue; /* path was GC'ed, probably */
-        Activity act(*logger, lvlChatty, format("hashing files in ‘%1%’") % i);
+        //Activity act(*logger, lvlChatty, format("hashing files in ‘%1%’") % i);
         optimisePath_(stats, realStoreDir + "/" + baseNameOf(i), inodeHash);
     }
 }
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 8405c66dd476..e6cbd53dc80a 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -167,7 +167,7 @@ void checkStoreName(const string & name)
    collisions (for security).  For instance, it shouldn't be feasible
    to come up with a derivation whose output path collides with the
    path for a copied source.  The former would have a <s> starting with
-   "output:out:", while the latter would have a <2> starting with
+   "output:out:", while the latter would have a <s> starting with
    "source:".
 */
 
@@ -822,7 +822,7 @@ void copyPaths(ref<Store> from, ref<Store> to, const PathSet & storePaths,
 
     std::string copiedLabel = "copied";
 
-    logger->setExpected(copiedLabel, missing.size());
+    //logger->setExpected(copiedLabel, missing.size());
 
     ThreadPool pool;
 
@@ -838,13 +838,14 @@ void copyPaths(ref<Store> from, ref<Store> to, const PathSet & storePaths,
             checkInterrupt();
 
             if (!to->isValidPath(storePath)) {
-                Activity act(*logger, lvlInfo, format("copying ‘%s’...") % storePath);
+                //Activity act(*logger, lvlInfo, format("copying ‘%s’...") % storePath);
 
                 copyStorePath(from, to, storePath, false, dontCheckSigs);
 
-                logger->incProgress(copiedLabel);
+                //logger->incProgress(copiedLabel);
             } else
-                logger->incExpected(copiedLabel, -1);
+                ;
+                //logger->incExpected(copiedLabel, -1);
         });
 
     pool.process();
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index b06f5d86a93a..929c95a0f2f8 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -113,9 +113,8 @@ struct ValidPathInfo
     uint64_t narSize = 0; // 0 = unknown
     uint64_t id; // internal use only
 
-    /* Whether the path is ultimately trusted, that is, it was built
-       locally or is content-addressable (e.g. added via addToStore()
-       or the result of a fixed-output derivation). */
+    /* Whether the path is ultimately trusted, that is, it's a
+       derivation output that was built locally. */
     bool ultimate = false;
 
     StringSet sigs; // note: not necessarily verified
diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
index afcc2ec58543..2d0acca24216 100644
--- a/src/libutil/logging.cc
+++ b/src/libutil/logging.cc
@@ -1,6 +1,8 @@
 #include "logging.hh"
 #include "util.hh"
 
+#include <atomic>
+
 namespace nix {
 
 Logger * logger = makeDefaultLogger();
@@ -42,12 +44,7 @@ public:
         writeToStderr(prefix + (tty ? fs.s : filterANSIEscapes(fs.s)) + "\n");
     }
 
-    void startActivity(Activity & activity, Verbosity lvl, const FormatOrString & fs) override
-    {
-        log(lvl, fs);
-    }
-
-    void stopActivity(Activity & activity) override
+    void event(const Event & ev) override
     {
     }
 };
@@ -79,4 +76,8 @@ Logger * makeDefaultLogger()
     return new SimpleLogger();
 }
 
+std::atomic<uint64_t> Activity::nextId{(uint64_t) getpid() << 32};
+
+Activity::Activity() : id(nextId++) { };
+
 }
diff --git a/src/libutil/logging.hh b/src/libutil/logging.hh
index 81aebccdca45..ddfc336fee07 100644
--- a/src/libutil/logging.hh
+++ b/src/libutil/logging.hh
@@ -13,7 +13,64 @@ typedef enum {
     lvlVomit
 } Verbosity;
 
-class Activity;
+class Activity
+{
+    static std::atomic<uint64_t> nextId;
+public:
+    typedef uint64_t t;
+    const t id;
+    Activity();
+    Activity(const Activity & act) : id(act.id) { };
+    Activity(uint64_t id) : id(id) { };
+};
+
+typedef enum {
+    evBuildCreated = 0,
+    evBuildStarted = 1,
+    evBuildOutput = 2,
+    evBuildFinished = 3,
+    evDownloadCreated = 4,
+    evDownloadDestroyed = 5,
+    evDownloadProgress = 6,
+    evDownloadSucceeded = 7,
+    evSubstitutionCreated = 8,
+    evSubstitutionStarted = 9,
+    evSubstitutionFinished = 10,
+} EventType;
+
+struct Event
+{
+    struct Field
+    {
+        // FIXME: use std::variant.
+        enum { tInt, tString } type;
+        uint64_t i = 0;
+        std::string s;
+        Field(const std::string & s) : type(tString), s(s) { }
+        Field(const char * s) : type(tString), s(s) { }
+        Field(const uint64_t & i) : type(tInt), i(i) { }
+        Field(const Activity & act) : type(tInt), i(act.id) { }
+    };
+
+    typedef std::vector<Field> Fields;
+
+    EventType type;
+    Fields fields;
+
+    std::string getS(size_t n) const
+    {
+        assert(n < fields.size());
+        assert(fields[n].type == Field::tString);
+        return fields[n].s;
+    }
+
+    uint64_t getI(size_t n) const
+    {
+        assert(n < fields.size());
+        assert(fields[n].type == Field::tInt);
+        return fields[n].i;
+    }
+};
 
 class Logger
 {
@@ -32,34 +89,16 @@ public:
 
     virtual void warn(const std::string & msg);
 
-    virtual void setExpected(const std::string & label, uint64_t value = 1) { }
-    virtual void setProgress(const std::string & label, uint64_t value = 1) { }
-    virtual void incExpected(const std::string & label, uint64_t value = 1) { }
-    virtual void incProgress(const std::string & label, uint64_t value = 1) { }
-
-private:
-
-    virtual void startActivity(Activity & activity, Verbosity lvl, const FormatOrString & fs) = 0;
-
-    virtual void stopActivity(Activity & activity) = 0;
-
-};
-
-class Activity
-{
-public:
-    Logger & logger;
-
-    Activity(Logger & logger, Verbosity lvl, const FormatOrString & fs)
-        : logger(logger)
+    template<typename... Args>
+    void event(EventType type, const Args & ... args)
     {
-        logger.startActivity(*this, lvl, fs);
+        Event ev;
+        ev.type = type;
+        nop{(ev.fields.emplace_back(Event::Field(args)), 1)...};
+        event(ev);
     }
 
-    ~Activity()
-    {
-        logger.stopActivity(*this);
-    }
+    virtual void event(const Event & ev) = 0;
 };
 
 extern Logger * logger;
@@ -88,7 +127,7 @@ template<typename... Args>
 inline void warn(const std::string & fs, Args... args)
 {
     boost::format f(fs);
-    formatHelper(f, args...);
+    nop{boost::io::detail::feed(f, args)...};
     logger->warn(f.str());
 }
 
diff --git a/src/libutil/types.hh b/src/libutil/types.hh
index 1429c238513b..9f32d31addbf 100644
--- a/src/libutil/types.hh
+++ b/src/libutil/types.hh
@@ -32,6 +32,11 @@ using std::vector;
 using boost::format;
 
 
+/* A variadic template that does nothing. Useful to call a function
+   for all variadic arguments but ignoring the result. */
+struct nop { template<typename... T> nop(T...) {} };
+
+
 struct FormatOrString
 {
     string s;
@@ -46,16 +51,6 @@ struct FormatOrString
    ... a_n’. However, ‘fmt(s)’ is equivalent to ‘s’ (so no %-expansion
    takes place). */
 
-inline void formatHelper(boost::format & f)
-{
-}
-
-template<typename T, typename... Args>
-inline void formatHelper(boost::format & f, T x, Args... args)
-{
-    formatHelper(f % x, args...);
-}
-
 inline std::string fmt(const std::string & s)
 {
     return s;
@@ -75,7 +70,7 @@ template<typename... Args>
 inline std::string fmt(const std::string & fs, Args... args)
 {
     boost::format f(fs);
-    formatHelper(f, args...);
+    nop{boost::io::detail::feed(f, args)...};
     return f.str();
 }
 
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 1d1f68fc8452..16f4b232e6c5 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -372,7 +372,7 @@ void deletePath(const Path & path)
 
 void deletePath(const Path & path, unsigned long long & bytesFreed)
 {
-    Activity act(*logger, lvlDebug, format("recursively deleting path ‘%1%’") % path);
+    //Activity act(*logger, lvlDebug, format("recursively deleting path ‘%1%’") % path);
     bytesFreed = 0;
     _deletePath(path, bytesFreed);
 }
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 5a9c9513fd5c..7ea32e8d9f14 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -364,6 +364,8 @@ void ignoreException();
 #define ANSI_NORMAL "\e[0m"
 #define ANSI_BOLD "\e[1m"
 #define ANSI_RED "\e[31;1m"
+#define ANSI_GREEN "\e[32;1m"
+#define ANSI_BLUE "\e[34;1m"
 
 
 /* Filter out ANSI escape codes from the given string. If ‘nixOnly’ is
diff --git a/src/linenoise/LICENSE b/src/linenoise/LICENSE
new file mode 100644
index 000000000000..18e814865a54
--- /dev/null
+++ b/src/linenoise/LICENSE
@@ -0,0 +1,25 @@
+Copyright (c) 2010-2014, Salvatore Sanfilippo <antirez at gmail dot com>
+Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice,
+  this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/src/linenoise/linenoise.c b/src/linenoise/linenoise.c
new file mode 100644
index 000000000000..fce14a7c53a3
--- /dev/null
+++ b/src/linenoise/linenoise.c
@@ -0,0 +1,1199 @@
+/* linenoise.c -- guerrilla line editing library against the idea that a
+ * line editing lib needs to be 20,000 lines of C code.
+ *
+ * You can find the latest source code at:
+ *
+ *   http://github.com/antirez/linenoise
+ *
+ * Does a number of crazy assumptions that happen to be true in 99.9999% of
+ * the 2010 UNIX computers around.
+ *
+ * ------------------------------------------------------------------------
+ *
+ * Copyright (c) 2010-2016, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *  *  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *  *  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ------------------------------------------------------------------------
+ *
+ * References:
+ * - http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+ * - http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
+ *
+ * Todo list:
+ * - Filter bogus Ctrl+<char> combinations.
+ * - Win32 support
+ *
+ * Bloat:
+ * - History search like Ctrl+r in readline?
+ *
+ * List of escape sequences used by this program, we do everything just
+ * with three sequences. In order to be so cheap we may have some
+ * flickering effect with some slow terminal, but the lesser sequences
+ * the more compatible.
+ *
+ * EL (Erase Line)
+ *    Sequence: ESC [ n K
+ *    Effect: if n is 0 or missing, clear from cursor to end of line
+ *    Effect: if n is 1, clear from beginning of line to cursor
+ *    Effect: if n is 2, clear entire line
+ *
+ * CUF (CUrsor Forward)
+ *    Sequence: ESC [ n C
+ *    Effect: moves cursor forward n chars
+ *
+ * CUB (CUrsor Backward)
+ *    Sequence: ESC [ n D
+ *    Effect: moves cursor backward n chars
+ *
+ * The following is used to get the terminal width if getting
+ * the width with the TIOCGWINSZ ioctl fails
+ *
+ * DSR (Device Status Report)
+ *    Sequence: ESC [ 6 n
+ *    Effect: reports the current cusor position as ESC [ n ; m R
+ *            where n is the row and m is the column
+ *
+ * When multi line mode is enabled, we also use an additional escape
+ * sequence. However multi line editing is disabled by default.
+ *
+ * CUU (Cursor Up)
+ *    Sequence: ESC [ n A
+ *    Effect: moves cursor up of n chars.
+ *
+ * CUD (Cursor Down)
+ *    Sequence: ESC [ n B
+ *    Effect: moves cursor down of n chars.
+ *
+ * When linenoiseClearScreen() is called, two additional escape sequences
+ * are used in order to clear the screen and position the cursor at home
+ * position.
+ *
+ * CUP (Cursor position)
+ *    Sequence: ESC [ H
+ *    Effect: moves the cursor to upper left corner
+ *
+ * ED (Erase display)
+ *    Sequence: ESC [ 2 J
+ *    Effect: clear the whole screen
+ *
+ */
+
+#include <termios.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include "linenoise.h"
+
+#define LINENOISE_DEFAULT_HISTORY_MAX_LEN 100
+#define LINENOISE_MAX_LINE 4096
+static char *unsupported_term[] = {"dumb","cons25","emacs",NULL};
+static linenoiseCompletionCallback *completionCallback = NULL;
+static linenoiseHintsCallback *hintsCallback = NULL;
+static linenoiseFreeHintsCallback *freeHintsCallback = NULL;
+
+static struct termios orig_termios; /* In order to restore at exit.*/
+static int rawmode = 0; /* For atexit() function to check if restore is needed*/
+static int mlmode = 0;  /* Multi line mode. Default is single line. */
+static int atexit_registered = 0; /* Register atexit just 1 time. */
+static int history_max_len = LINENOISE_DEFAULT_HISTORY_MAX_LEN;
+static int history_len = 0;
+static char **history = NULL;
+
+/* The linenoiseState structure represents the state during line editing.
+ * We pass this state to functions implementing specific editing
+ * functionalities. */
+struct linenoiseState {
+    int ifd;            /* Terminal stdin file descriptor. */
+    int ofd;            /* Terminal stdout file descriptor. */
+    char *buf;          /* Edited line buffer. */
+    size_t buflen;      /* Edited line buffer size. */
+    const char *prompt; /* Prompt to display. */
+    size_t plen;        /* Prompt length. */
+    size_t pos;         /* Current cursor position. */
+    size_t oldpos;      /* Previous refresh cursor position. */
+    size_t len;         /* Current edited line length. */
+    size_t cols;        /* Number of columns in terminal. */
+    size_t maxrows;     /* Maximum num of rows used so far (multiline mode) */
+    int history_index;  /* The history index we are currently editing. */
+};
+
+enum KEY_ACTION{
+	KEY_NULL = 0,	    /* NULL */
+	CTRL_A = 1,         /* Ctrl+a */
+	CTRL_B = 2,         /* Ctrl-b */
+	CTRL_C = 3,         /* Ctrl-c */
+	CTRL_D = 4,         /* Ctrl-d */
+	CTRL_E = 5,         /* Ctrl-e */
+	CTRL_F = 6,         /* Ctrl-f */
+	CTRL_H = 8,         /* Ctrl-h */
+	TAB = 9,            /* Tab */
+	CTRL_K = 11,        /* Ctrl+k */
+	CTRL_L = 12,        /* Ctrl+l */
+	ENTER = 13,         /* Enter */
+	CTRL_N = 14,        /* Ctrl-n */
+	CTRL_P = 16,        /* Ctrl-p */
+	CTRL_T = 20,        /* Ctrl-t */
+	CTRL_U = 21,        /* Ctrl+u */
+	CTRL_W = 23,        /* Ctrl+w */
+	ESC = 27,           /* Escape */
+	BACKSPACE =  127    /* Backspace */
+};
+
+static void linenoiseAtExit(void);
+int linenoiseHistoryAdd(const char *line);
+static void refreshLine(struct linenoiseState *l);
+
+/* Debugging macro. */
+#if 0
+FILE *lndebug_fp = NULL;
+#define lndebug(...) \
+    do { \
+        if (lndebug_fp == NULL) { \
+            lndebug_fp = fopen("/tmp/lndebug.txt","a"); \
+            fprintf(lndebug_fp, \
+            "[%d %d %d] p: %d, rows: %d, rpos: %d, max: %d, oldmax: %d\n", \
+            (int)l->len,(int)l->pos,(int)l->oldpos,plen,rows,rpos, \
+            (int)l->maxrows,old_rows); \
+        } \
+        fprintf(lndebug_fp, ", " __VA_ARGS__); \
+        fflush(lndebug_fp); \
+    } while (0)
+#else
+#define lndebug(fmt, ...)
+#endif
+
+/* ======================= Low level terminal handling ====================== */
+
+/* Set if to use or not the multi line mode. */
+void linenoiseSetMultiLine(int ml) {
+    mlmode = ml;
+}
+
+/* Return true if the terminal name is in the list of terminals we know are
+ * not able to understand basic escape sequences. */
+static int isUnsupportedTerm(void) {
+    char *term = getenv("TERM");
+    int j;
+
+    if (term == NULL) return 0;
+    for (j = 0; unsupported_term[j]; j++)
+        if (!strcasecmp(term,unsupported_term[j])) return 1;
+    return 0;
+}
+
+/* Raw mode: 1960 magic shit. */
+static int enableRawMode(int fd) {
+    struct termios raw;
+
+    if (!isatty(STDIN_FILENO)) goto fatal;
+    if (!atexit_registered) {
+        atexit(linenoiseAtExit);
+        atexit_registered = 1;
+    }
+    if (tcgetattr(fd,&orig_termios) == -1) goto fatal;
+
+    raw = orig_termios;  /* modify the original mode */
+    /* input modes: no break, no CR to NL, no parity check, no strip char,
+     * no start/stop output control. */
+    raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+    /* output modes - disable post processing */
+    raw.c_oflag &= ~(OPOST);
+    /* control modes - set 8 bit chars */
+    raw.c_cflag |= (CS8);
+    /* local modes - choing off, canonical off, no extended functions,
+     * no signal chars (^Z,^C) */
+    raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+    /* control chars - set return condition: min number of bytes and timer.
+     * We want read to return every single byte, without timeout. */
+    raw.c_cc[VMIN] = 1; raw.c_cc[VTIME] = 0; /* 1 byte, no timer */
+
+    /* put terminal in raw mode after flushing */
+    if (tcsetattr(fd,TCSAFLUSH,&raw) < 0) goto fatal;
+    rawmode = 1;
+    return 0;
+
+fatal:
+    errno = ENOTTY;
+    return -1;
+}
+
+static void disableRawMode(int fd) {
+    /* Don't even check the return value as it's too late. */
+    if (rawmode && tcsetattr(fd,TCSAFLUSH,&orig_termios) != -1)
+        rawmode = 0;
+}
+
+/* Use the ESC [6n escape sequence to query the horizontal cursor position
+ * and return it. On error -1 is returned, on success the position of the
+ * cursor. */
+static int getCursorPosition(int ifd, int ofd) {
+    char buf[32];
+    int cols, rows;
+    unsigned int i = 0;
+
+    /* Report cursor location */
+    if (write(ofd, "\x1b[6n", 4) != 4) return -1;
+
+    /* Read the response: ESC [ rows ; cols R */
+    while (i < sizeof(buf)-1) {
+        if (read(ifd,buf+i,1) != 1) break;
+        if (buf[i] == 'R') break;
+        i++;
+    }
+    buf[i] = '\0';
+
+    /* Parse it. */
+    if (buf[0] != ESC || buf[1] != '[') return -1;
+    if (sscanf(buf+2,"%d;%d",&rows,&cols) != 2) return -1;
+    return cols;
+}
+
+/* Try to get the number of columns in the current terminal, or assume 80
+ * if it fails. */
+static int getColumns(int ifd, int ofd) {
+    struct winsize ws;
+
+    if (ioctl(1, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
+        /* ioctl() failed. Try to query the terminal itself. */
+        int start, cols;
+
+        /* Get the initial position so we can restore it later. */
+        start = getCursorPosition(ifd,ofd);
+        if (start == -1) goto failed;
+
+        /* Go to right margin and get position. */
+        if (write(ofd,"\x1b[999C",6) != 6) goto failed;
+        cols = getCursorPosition(ifd,ofd);
+        if (cols == -1) goto failed;
+
+        /* Restore position. */
+        if (cols > start) {
+            char seq[32];
+            snprintf(seq,32,"\x1b[%dD",cols-start);
+            if (write(ofd,seq,strlen(seq)) == -1) {
+                /* Can't recover... */
+            }
+        }
+        return cols;
+    } else {
+        return ws.ws_col;
+    }
+
+failed:
+    return 80;
+}
+
+/* Clear the screen. Used to handle ctrl+l */
+void linenoiseClearScreen(void) {
+    if (write(STDOUT_FILENO,"\x1b[H\x1b[2J",7) <= 0) {
+        /* nothing to do, just to avoid warning. */
+    }
+}
+
+/* Beep, used for completion when there is nothing to complete or when all
+ * the choices were already shown. */
+static void linenoiseBeep(void) {
+    fprintf(stderr, "\x7");
+    fflush(stderr);
+}
+
+/* ============================== Completion ================================ */
+
+/* Free a list of completion option populated by linenoiseAddCompletion(). */
+static void freeCompletions(linenoiseCompletions *lc) {
+    size_t i;
+    for (i = 0; i < lc->len; i++)
+        free(lc->cvec[i]);
+    if (lc->cvec != NULL)
+        free(lc->cvec);
+}
+
+/* This is an helper function for linenoiseEdit() and is called when the
+ * user types the <tab> key in order to complete the string currently in the
+ * input.
+ *
+ * The state of the editing is encapsulated into the pointed linenoiseState
+ * structure as described in the structure definition. */
+static int completeLine(struct linenoiseState *ls) {
+    linenoiseCompletions lc = { 0, NULL };
+    int nread, nwritten;
+    char c = 0;
+
+    completionCallback(ls->buf,&lc);
+    if (lc.len == 0) {
+        linenoiseBeep();
+    } else {
+        size_t stop = 0, i = 0;
+
+        while(!stop) {
+            /* Show completion or original buffer */
+            if (i < lc.len) {
+                struct linenoiseState saved = *ls;
+
+                ls->len = ls->pos = strlen(lc.cvec[i]);
+                ls->buf = lc.cvec[i];
+                refreshLine(ls);
+                ls->len = saved.len;
+                ls->pos = saved.pos;
+                ls->buf = saved.buf;
+            } else {
+                refreshLine(ls);
+            }
+
+            nread = read(ls->ifd,&c,1);
+            if (nread <= 0) {
+                freeCompletions(&lc);
+                return -1;
+            }
+
+            switch(c) {
+                case 9: /* tab */
+                    i = (i+1) % (lc.len+1);
+                    if (i == lc.len) linenoiseBeep();
+                    break;
+                case 27: /* escape */
+                    /* Re-show original buffer */
+                    if (i < lc.len) refreshLine(ls);
+                    stop = 1;
+                    break;
+                default:
+                    /* Update buffer and return */
+                    if (i < lc.len) {
+                        nwritten = snprintf(ls->buf,ls->buflen,"%s",lc.cvec[i]);
+                        ls->len = ls->pos = nwritten;
+                    }
+                    stop = 1;
+                    break;
+            }
+        }
+    }
+
+    freeCompletions(&lc);
+    return c; /* Return last read character */
+}
+
+/* Register a callback function to be called for tab-completion. */
+void linenoiseSetCompletionCallback(linenoiseCompletionCallback *fn) {
+    completionCallback = fn;
+}
+
+/* Register a hits function to be called to show hits to the user at the
+ * right of the prompt. */
+void linenoiseSetHintsCallback(linenoiseHintsCallback *fn) {
+    hintsCallback = fn;
+}
+
+/* Register a function to free the hints returned by the hints callback
+ * registered with linenoiseSetHintsCallback(). */
+void linenoiseSetFreeHintsCallback(linenoiseFreeHintsCallback *fn) {
+    freeHintsCallback = fn;
+}
+
+/* This function is used by the callback function registered by the user
+ * in order to add completion options given the input string when the
+ * user typed <tab>. See the example.c source code for a very easy to
+ * understand example. */
+void linenoiseAddCompletion(linenoiseCompletions *lc, const char *str) {
+    size_t len = strlen(str);
+    char *copy, **cvec;
+
+    copy = malloc(len+1);
+    if (copy == NULL) return;
+    memcpy(copy,str,len+1);
+    cvec = realloc(lc->cvec,sizeof(char*)*(lc->len+1));
+    if (cvec == NULL) {
+        free(copy);
+        return;
+    }
+    lc->cvec = cvec;
+    lc->cvec[lc->len++] = copy;
+}
+
+/* =========================== Line editing ================================= */
+
+/* We define a very simple "append buffer" structure, that is an heap
+ * allocated string where we can append to. This is useful in order to
+ * write all the escape sequences in a buffer and flush them to the standard
+ * output in a single call, to avoid flickering effects. */
+struct abuf {
+    char *b;
+    int len;
+};
+
+static void abInit(struct abuf *ab) {
+    ab->b = NULL;
+    ab->len = 0;
+}
+
+static void abAppend(struct abuf *ab, const char *s, int len) {
+    char *new = realloc(ab->b,ab->len+len);
+
+    if (new == NULL) return;
+    memcpy(new+ab->len,s,len);
+    ab->b = new;
+    ab->len += len;
+}
+
+static void abFree(struct abuf *ab) {
+    free(ab->b);
+}
+
+/* Helper of refreshSingleLine() and refreshMultiLine() to show hints
+ * to the right of the prompt. */
+void refreshShowHints(struct abuf *ab, struct linenoiseState *l, int plen) {
+    char seq[64];
+    if (hintsCallback && plen+l->len < l->cols) {
+        int color = -1, bold = 0;
+        char *hint = hintsCallback(l->buf,&color,&bold);
+        if (hint) {
+            int hintlen = strlen(hint);
+            int hintmaxlen = l->cols-(plen+l->len);
+            if (hintlen > hintmaxlen) hintlen = hintmaxlen;
+            if (bold == 1 && color == -1) color = 37;
+            if (color != -1 || bold != 0)
+                snprintf(seq,64,"\033[%d;%d;49m",bold,color);
+            abAppend(ab,seq,strlen(seq));
+            abAppend(ab,hint,hintlen);
+            if (color != -1 || bold != 0)
+                abAppend(ab,"\033[0m",4);
+            /* Call the function to free the hint returned. */
+            if (freeHintsCallback) freeHintsCallback(hint);
+        }
+    }
+}
+
+/* Single line low level line refresh.
+ *
+ * Rewrite the currently edited line accordingly to the buffer content,
+ * cursor position, and number of columns of the terminal. */
+static void refreshSingleLine(struct linenoiseState *l) {
+    char seq[64];
+    size_t plen = strlen(l->prompt);
+    int fd = l->ofd;
+    char *buf = l->buf;
+    size_t len = l->len;
+    size_t pos = l->pos;
+    struct abuf ab;
+
+    while((plen+pos) >= l->cols) {
+        buf++;
+        len--;
+        pos--;
+    }
+    while (plen+len > l->cols) {
+        len--;
+    }
+
+    abInit(&ab);
+    /* Cursor to left edge */
+    snprintf(seq,64,"\r");
+    abAppend(&ab,seq,strlen(seq));
+    /* Write the prompt and the current buffer content */
+    abAppend(&ab,l->prompt,strlen(l->prompt));
+    abAppend(&ab,buf,len);
+    /* Show hits if any. */
+    refreshShowHints(&ab,l,plen);
+    /* Erase to right */
+    snprintf(seq,64,"\x1b[0K");
+    abAppend(&ab,seq,strlen(seq));
+    /* Move cursor to original position. */
+    snprintf(seq,64,"\r\x1b[%dC", (int)(pos+plen));
+    abAppend(&ab,seq,strlen(seq));
+    if (write(fd,ab.b,ab.len) == -1) {} /* Can't recover from write error. */
+    abFree(&ab);
+}
+
+/* Multi line low level line refresh.
+ *
+ * Rewrite the currently edited line accordingly to the buffer content,
+ * cursor position, and number of columns of the terminal. */
+static void refreshMultiLine(struct linenoiseState *l) {
+    char seq[64];
+    int plen = strlen(l->prompt);
+    int rows = (plen+l->len+l->cols-1)/l->cols; /* rows used by current buf. */
+    int rpos = (plen+l->oldpos+l->cols)/l->cols; /* cursor relative row. */
+    int rpos2; /* rpos after refresh. */
+    int col; /* colum position, zero-based. */
+    int old_rows = l->maxrows;
+    int fd = l->ofd, j;
+    struct abuf ab;
+
+    /* Update maxrows if needed. */
+    if (rows > (int)l->maxrows) l->maxrows = rows;
+
+    /* First step: clear all the lines used before. To do so start by
+     * going to the last row. */
+    abInit(&ab);
+    if (old_rows-rpos > 0) {
+        lndebug("go down %d", old_rows-rpos);
+        snprintf(seq,64,"\x1b[%dB", old_rows-rpos);
+        abAppend(&ab,seq,strlen(seq));
+    }
+
+    /* Now for every row clear it, go up. */
+    for (j = 0; j < old_rows-1; j++) {
+        lndebug("clear+up");
+        snprintf(seq,64,"\r\x1b[0K\x1b[1A");
+        abAppend(&ab,seq,strlen(seq));
+    }
+
+    /* Clean the top line. */
+    lndebug("clear");
+    snprintf(seq,64,"\r\x1b[0K");
+    abAppend(&ab,seq,strlen(seq));
+
+    /* Write the prompt and the current buffer content */
+    abAppend(&ab,l->prompt,strlen(l->prompt));
+    abAppend(&ab,l->buf,l->len);
+
+    /* Show hits if any. */
+    refreshShowHints(&ab,l,plen);
+
+    /* If we are at the very end of the screen with our prompt, we need to
+     * emit a newline and move the prompt to the first column. */
+    if (l->pos &&
+        l->pos == l->len &&
+        (l->pos+plen) % l->cols == 0)
+    {
+        lndebug("<newline>");
+        abAppend(&ab,"\n",1);
+        snprintf(seq,64,"\r");
+        abAppend(&ab,seq,strlen(seq));
+        rows++;
+        if (rows > (int)l->maxrows) l->maxrows = rows;
+    }
+
+    /* Move cursor to right position. */
+    rpos2 = (plen+l->pos+l->cols)/l->cols; /* current cursor relative row. */
+    lndebug("rpos2 %d", rpos2);
+
+    /* Go up till we reach the expected positon. */
+    if (rows-rpos2 > 0) {
+        lndebug("go-up %d", rows-rpos2);
+        snprintf(seq,64,"\x1b[%dA", rows-rpos2);
+        abAppend(&ab,seq,strlen(seq));
+    }
+
+    /* Set column. */
+    col = (plen+(int)l->pos) % (int)l->cols;
+    lndebug("set col %d", 1+col);
+    if (col)
+        snprintf(seq,64,"\r\x1b[%dC", col);
+    else
+        snprintf(seq,64,"\r");
+    abAppend(&ab,seq,strlen(seq));
+
+    lndebug("\n");
+    l->oldpos = l->pos;
+
+    if (write(fd,ab.b,ab.len) == -1) {} /* Can't recover from write error. */
+    abFree(&ab);
+}
+
+/* Calls the two low level functions refreshSingleLine() or
+ * refreshMultiLine() according to the selected mode. */
+static void refreshLine(struct linenoiseState *l) {
+    if (mlmode)
+        refreshMultiLine(l);
+    else
+        refreshSingleLine(l);
+}
+
+/* Insert the character 'c' at cursor current position.
+ *
+ * On error writing to the terminal -1 is returned, otherwise 0. */
+int linenoiseEditInsert(struct linenoiseState *l, char c) {
+    if (l->len < l->buflen) {
+        if (l->len == l->pos) {
+            l->buf[l->pos] = c;
+            l->pos++;
+            l->len++;
+            l->buf[l->len] = '\0';
+            if ((!mlmode && l->plen+l->len < l->cols && !hintsCallback)) {
+                /* Avoid a full update of the line in the
+                 * trivial case. */
+                if (write(l->ofd,&c,1) == -1) return -1;
+            } else {
+                refreshLine(l);
+            }
+        } else {
+            memmove(l->buf+l->pos+1,l->buf+l->pos,l->len-l->pos);
+            l->buf[l->pos] = c;
+            l->len++;
+            l->pos++;
+            l->buf[l->len] = '\0';
+            refreshLine(l);
+        }
+    }
+    return 0;
+}
+
+/* Move cursor on the left. */
+void linenoiseEditMoveLeft(struct linenoiseState *l) {
+    if (l->pos > 0) {
+        l->pos--;
+        refreshLine(l);
+    }
+}
+
+/* Move cursor on the right. */
+void linenoiseEditMoveRight(struct linenoiseState *l) {
+    if (l->pos != l->len) {
+        l->pos++;
+        refreshLine(l);
+    }
+}
+
+/* Move cursor to the start of the line. */
+void linenoiseEditMoveHome(struct linenoiseState *l) {
+    if (l->pos != 0) {
+        l->pos = 0;
+        refreshLine(l);
+    }
+}
+
+/* Move cursor to the end of the line. */
+void linenoiseEditMoveEnd(struct linenoiseState *l) {
+    if (l->pos != l->len) {
+        l->pos = l->len;
+        refreshLine(l);
+    }
+}
+
+/* Substitute the currently edited line with the next or previous history
+ * entry as specified by 'dir'. */
+#define LINENOISE_HISTORY_NEXT 0
+#define LINENOISE_HISTORY_PREV 1
+void linenoiseEditHistoryNext(struct linenoiseState *l, int dir) {
+    if (history_len > 1) {
+        /* Update the current history entry before to
+         * overwrite it with the next one. */
+        free(history[history_len - 1 - l->history_index]);
+        history[history_len - 1 - l->history_index] = strdup(l->buf);
+        /* Show the new entry */
+        l->history_index += (dir == LINENOISE_HISTORY_PREV) ? 1 : -1;
+        if (l->history_index < 0) {
+            l->history_index = 0;
+            return;
+        } else if (l->history_index >= history_len) {
+            l->history_index = history_len-1;
+            return;
+        }
+        strncpy(l->buf,history[history_len - 1 - l->history_index],l->buflen);
+        l->buf[l->buflen-1] = '\0';
+        l->len = l->pos = strlen(l->buf);
+        refreshLine(l);
+    }
+}
+
+/* Delete the character at the right of the cursor without altering the cursor
+ * position. Basically this is what happens with the "Delete" keyboard key. */
+void linenoiseEditDelete(struct linenoiseState *l) {
+    if (l->len > 0 && l->pos < l->len) {
+        memmove(l->buf+l->pos,l->buf+l->pos+1,l->len-l->pos-1);
+        l->len--;
+        l->buf[l->len] = '\0';
+        refreshLine(l);
+    }
+}
+
+/* Backspace implementation. */
+void linenoiseEditBackspace(struct linenoiseState *l) {
+    if (l->pos > 0 && l->len > 0) {
+        memmove(l->buf+l->pos-1,l->buf+l->pos,l->len-l->pos);
+        l->pos--;
+        l->len--;
+        l->buf[l->len] = '\0';
+        refreshLine(l);
+    }
+}
+
+/* Delete the previosu word, maintaining the cursor at the start of the
+ * current word. */
+void linenoiseEditDeletePrevWord(struct linenoiseState *l) {
+    size_t old_pos = l->pos;
+    size_t diff;
+
+    while (l->pos > 0 && l->buf[l->pos-1] == ' ')
+        l->pos--;
+    while (l->pos > 0 && l->buf[l->pos-1] != ' ')
+        l->pos--;
+    diff = old_pos - l->pos;
+    memmove(l->buf+l->pos,l->buf+old_pos,l->len-old_pos+1);
+    l->len -= diff;
+    refreshLine(l);
+}
+
+/* This function is the core of the line editing capability of linenoise.
+ * It expects 'fd' to be already in "raw mode" so that every key pressed
+ * will be returned ASAP to read().
+ *
+ * The resulting string is put into 'buf' when the user type enter, or
+ * when ctrl+d is typed.
+ *
+ * The function returns the length of the current buffer. */
+static int linenoiseEdit(int stdin_fd, int stdout_fd, char *buf, size_t buflen, const char *prompt)
+{
+    struct linenoiseState l;
+
+    /* Populate the linenoise state that we pass to functions implementing
+     * specific editing functionalities. */
+    l.ifd = stdin_fd;
+    l.ofd = stdout_fd;
+    l.buf = buf;
+    l.buflen = buflen;
+    l.prompt = prompt;
+    l.plen = strlen(prompt);
+    l.oldpos = l.pos = 0;
+    l.len = 0;
+    l.cols = getColumns(stdin_fd, stdout_fd);
+    l.maxrows = 0;
+    l.history_index = 0;
+
+    /* Buffer starts empty. */
+    l.buf[0] = '\0';
+    l.buflen--; /* Make sure there is always space for the nulterm */
+
+    /* The latest history entry is always our current buffer, that
+     * initially is just an empty string. */
+    linenoiseHistoryAdd("");
+
+    if (write(l.ofd,prompt,l.plen) == -1) return -1;
+    while(1) {
+        char c;
+        int nread;
+        char seq[3];
+
+        nread = read(l.ifd,&c,1);
+        if (nread <= 0) return l.len;
+
+        /* Only autocomplete when the callback is set. It returns < 0 when
+         * there was an error reading from fd. Otherwise it will return the
+         * character that should be handled next. */
+        if (c == 9 && completionCallback != NULL) {
+            c = completeLine(&l);
+            /* Return on errors */
+            if (c < 0) return l.len;
+            /* Read next character when 0 */
+            if (c == 0) continue;
+        }
+
+        switch(c) {
+        case ENTER:    /* enter */
+            history_len--;
+            free(history[history_len]);
+            if (mlmode) linenoiseEditMoveEnd(&l);
+            if (hintsCallback) {
+                /* Force a refresh without hints to leave the previous
+                 * line as the user typed it after a newline. */
+                linenoiseHintsCallback *hc = hintsCallback;
+                hintsCallback = NULL;
+                refreshLine(&l);
+                hintsCallback = hc;
+            }
+            return (int)l.len;
+        case CTRL_C:     /* ctrl-c */
+            errno = EAGAIN;
+            return -1;
+        case BACKSPACE:   /* backspace */
+        case 8:     /* ctrl-h */
+            linenoiseEditBackspace(&l);
+            break;
+        case CTRL_D:     /* ctrl-d, remove char at right of cursor, or if the
+                            line is empty, act as end-of-file. */
+            if (l.len > 0) {
+                linenoiseEditDelete(&l);
+            } else {
+                history_len--;
+                free(history[history_len]);
+                return -1;
+            }
+            break;
+        case CTRL_T:    /* ctrl-t, swaps current character with previous. */
+            if (l.pos > 0 && l.pos < l.len) {
+                int aux = buf[l.pos-1];
+                buf[l.pos-1] = buf[l.pos];
+                buf[l.pos] = aux;
+                if (l.pos != l.len-1) l.pos++;
+                refreshLine(&l);
+            }
+            break;
+        case CTRL_B:     /* ctrl-b */
+            linenoiseEditMoveLeft(&l);
+            break;
+        case CTRL_F:     /* ctrl-f */
+            linenoiseEditMoveRight(&l);
+            break;
+        case CTRL_P:    /* ctrl-p */
+            linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_PREV);
+            break;
+        case CTRL_N:    /* ctrl-n */
+            linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_NEXT);
+            break;
+        case ESC:    /* escape sequence */
+            /* Read the next two bytes representing the escape sequence.
+             * Use two calls to handle slow terminals returning the two
+             * chars at different times. */
+            if (read(l.ifd,seq,1) == -1) break;
+            if (read(l.ifd,seq+1,1) == -1) break;
+
+            /* ESC [ sequences. */
+            if (seq[0] == '[') {
+                if (seq[1] >= '0' && seq[1] <= '9') {
+                    /* Extended escape, read additional byte. */
+                    if (read(l.ifd,seq+2,1) == -1) break;
+                    if (seq[2] == '~') {
+                        switch(seq[1]) {
+                        case '3': /* Delete key. */
+                            linenoiseEditDelete(&l);
+                            break;
+                        }
+                    }
+                } else {
+                    switch(seq[1]) {
+                    case 'A': /* Up */
+                        linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_PREV);
+                        break;
+                    case 'B': /* Down */
+                        linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_NEXT);
+                        break;
+                    case 'C': /* Right */
+                        linenoiseEditMoveRight(&l);
+                        break;
+                    case 'D': /* Left */
+                        linenoiseEditMoveLeft(&l);
+                        break;
+                    case 'H': /* Home */
+                        linenoiseEditMoveHome(&l);
+                        break;
+                    case 'F': /* End*/
+                        linenoiseEditMoveEnd(&l);
+                        break;
+                    }
+                }
+            }
+
+            /* ESC O sequences. */
+            else if (seq[0] == 'O') {
+                switch(seq[1]) {
+                case 'H': /* Home */
+                    linenoiseEditMoveHome(&l);
+                    break;
+                case 'F': /* End*/
+                    linenoiseEditMoveEnd(&l);
+                    break;
+                }
+            }
+            break;
+        default:
+            if (linenoiseEditInsert(&l,c)) return -1;
+            break;
+        case CTRL_U: /* Ctrl+u, delete the whole line. */
+            buf[0] = '\0';
+            l.pos = l.len = 0;
+            refreshLine(&l);
+            break;
+        case CTRL_K: /* Ctrl+k, delete from current to end of line. */
+            buf[l.pos] = '\0';
+            l.len = l.pos;
+            refreshLine(&l);
+            break;
+        case CTRL_A: /* Ctrl+a, go to the start of the line */
+            linenoiseEditMoveHome(&l);
+            break;
+        case CTRL_E: /* ctrl+e, go to the end of the line */
+            linenoiseEditMoveEnd(&l);
+            break;
+        case CTRL_L: /* ctrl+l, clear screen */
+            linenoiseClearScreen();
+            refreshLine(&l);
+            break;
+        case CTRL_W: /* ctrl+w, delete previous word */
+            linenoiseEditDeletePrevWord(&l);
+            break;
+        }
+    }
+    return l.len;
+}
+
+/* This special mode is used by linenoise in order to print scan codes
+ * on screen for debugging / development purposes. It is implemented
+ * by the linenoise_example program using the --keycodes option. */
+void linenoisePrintKeyCodes(void) {
+    char quit[4];
+
+    printf("Linenoise key codes debugging mode.\n"
+            "Press keys to see scan codes. Type 'quit' at any time to exit.\n");
+    if (enableRawMode(STDIN_FILENO) == -1) return;
+    memset(quit,' ',4);
+    while(1) {
+        char c;
+        int nread;
+
+        nread = read(STDIN_FILENO,&c,1);
+        if (nread <= 0) continue;
+        memmove(quit,quit+1,sizeof(quit)-1); /* shift string to left. */
+        quit[sizeof(quit)-1] = c; /* Insert current char on the right. */
+        if (memcmp(quit,"quit",sizeof(quit)) == 0) break;
+
+        printf("'%c' %02x (%d) (type quit to exit)\n",
+            isprint(c) ? c : '?', (int)c, (int)c);
+        printf("\r"); /* Go left edge manually, we are in raw mode. */
+        fflush(stdout);
+    }
+    disableRawMode(STDIN_FILENO);
+}
+
+/* This function calls the line editing function linenoiseEdit() using
+ * the STDIN file descriptor set in raw mode. */
+static int linenoiseRaw(char *buf, size_t buflen, const char *prompt) {
+    int count;
+
+    if (buflen == 0) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    if (enableRawMode(STDIN_FILENO) == -1) return -1;
+    count = linenoiseEdit(STDIN_FILENO, STDOUT_FILENO, buf, buflen, prompt);
+    disableRawMode(STDIN_FILENO);
+    printf("\n");
+    return count;
+}
+
+/* This function is called when linenoise() is called with the standard
+ * input file descriptor not attached to a TTY. So for example when the
+ * program using linenoise is called in pipe or with a file redirected
+ * to its standard input. In this case, we want to be able to return the
+ * line regardless of its length (by default we are limited to 4k). */
+static char *linenoiseNoTTY(void) {
+    char *line = NULL;
+    size_t len = 0, maxlen = 0;
+
+    while(1) {
+        if (len == maxlen) {
+            if (maxlen == 0) maxlen = 16;
+            maxlen *= 2;
+            char *oldval = line;
+            line = realloc(line,maxlen);
+            if (line == NULL) {
+                if (oldval) free(oldval);
+                return NULL;
+            }
+        }
+        int c = fgetc(stdin);
+        if (c == EOF || c == '\n') {
+            if (c == EOF && len == 0) {
+                free(line);
+                return NULL;
+            } else {
+                line[len] = '\0';
+                return line;
+            }
+        } else {
+            line[len] = c;
+            len++;
+        }
+    }
+}
+
+/* The high level function that is the main API of the linenoise library.
+ * This function checks if the terminal has basic capabilities, just checking
+ * for a blacklist of stupid terminals, and later either calls the line
+ * editing function or uses dummy fgets() so that you will be able to type
+ * something even in the most desperate of the conditions. */
+char *linenoise(const char *prompt) {
+    char buf[LINENOISE_MAX_LINE];
+    int count;
+
+    if (!isatty(STDIN_FILENO)) {
+        /* Not a tty: read from file / pipe. In this mode we don't want any
+         * limit to the line size, so we call a function to handle that. */
+        return linenoiseNoTTY();
+    } else if (isUnsupportedTerm()) {
+        size_t len;
+
+        printf("%s",prompt);
+        fflush(stdout);
+        if (fgets(buf,LINENOISE_MAX_LINE,stdin) == NULL) return NULL;
+        len = strlen(buf);
+        while(len && (buf[len-1] == '\n' || buf[len-1] == '\r')) {
+            len--;
+            buf[len] = '\0';
+        }
+        return strdup(buf);
+    } else {
+        count = linenoiseRaw(buf,LINENOISE_MAX_LINE,prompt);
+        if (count == -1) return NULL;
+        return strdup(buf);
+    }
+}
+
+/* This is just a wrapper the user may want to call in order to make sure
+ * the linenoise returned buffer is freed with the same allocator it was
+ * created with. Useful when the main program is using an alternative
+ * allocator. */
+void linenoiseFree(void *ptr) {
+    free(ptr);
+}
+
+/* ================================ History ================================= */
+
+/* Free the history, but does not reset it. Only used when we have to
+ * exit() to avoid memory leaks are reported by valgrind & co. */
+static void freeHistory(void) {
+    if (history) {
+        int j;
+
+        for (j = 0; j < history_len; j++)
+            free(history[j]);
+        free(history);
+    }
+}
+
+/* At exit we'll try to fix the terminal to the initial conditions. */
+static void linenoiseAtExit(void) {
+    disableRawMode(STDIN_FILENO);
+    freeHistory();
+}
+
+/* This is the API call to add a new entry in the linenoise history.
+ * It uses a fixed array of char pointers that are shifted (memmoved)
+ * when the history max length is reached in order to remove the older
+ * entry and make room for the new one, so it is not exactly suitable for huge
+ * histories, but will work well for a few hundred of entries.
+ *
+ * Using a circular buffer is smarter, but a bit more complex to handle. */
+int linenoiseHistoryAdd(const char *line) {
+    char *linecopy;
+
+    if (history_max_len == 0) return 0;
+
+    /* Initialization on first call. */
+    if (history == NULL) {
+        history = malloc(sizeof(char*)*history_max_len);
+        if (history == NULL) return 0;
+        memset(history,0,(sizeof(char*)*history_max_len));
+    }
+
+    /* Don't add duplicated lines. */
+    if (history_len && !strcmp(history[history_len-1], line)) return 0;
+
+    /* Add an heap allocated copy of the line in the history.
+     * If we reached the max length, remove the older line. */
+    linecopy = strdup(line);
+    if (!linecopy) return 0;
+    if (history_len == history_max_len) {
+        free(history[0]);
+        memmove(history,history+1,sizeof(char*)*(history_max_len-1));
+        history_len--;
+    }
+    history[history_len] = linecopy;
+    history_len++;
+    return 1;
+}
+
+/* Set the maximum length for the history. This function can be called even
+ * if there is already some history, the function will make sure to retain
+ * just the latest 'len' elements if the new history length value is smaller
+ * than the amount of items already inside the history. */
+int linenoiseHistorySetMaxLen(int len) {
+    char **new;
+
+    if (len < 1) return 0;
+    if (history) {
+        int tocopy = history_len;
+
+        new = malloc(sizeof(char*)*len);
+        if (new == NULL) return 0;
+
+        /* If we can't copy everything, free the elements we'll not use. */
+        if (len < tocopy) {
+            int j;
+
+            for (j = 0; j < tocopy-len; j++) free(history[j]);
+            tocopy = len;
+        }
+        memset(new,0,sizeof(char*)*len);
+        memcpy(new,history+(history_len-tocopy), sizeof(char*)*tocopy);
+        free(history);
+        history = new;
+    }
+    history_max_len = len;
+    if (history_len > history_max_len)
+        history_len = history_max_len;
+    return 1;
+}
+
+/* Save the history in the specified file. On success 0 is returned
+ * otherwise -1 is returned. */
+int linenoiseHistorySave(const char *filename) {
+    mode_t old_umask = umask(S_IXUSR|S_IRWXG|S_IRWXO);
+    FILE *fp;
+    int j;
+
+    fp = fopen(filename,"w");
+    umask(old_umask);
+    if (fp == NULL) return -1;
+    chmod(filename,S_IRUSR|S_IWUSR);
+    for (j = 0; j < history_len; j++)
+        fprintf(fp,"%s\n",history[j]);
+    fclose(fp);
+    return 0;
+}
+
+/* Load the history from the specified file. If the file does not exist
+ * zero is returned and no operation is performed.
+ *
+ * If the file exists and the operation succeeded 0 is returned, otherwise
+ * on error -1 is returned. */
+int linenoiseHistoryLoad(const char *filename) {
+    FILE *fp = fopen(filename,"r");
+    char buf[LINENOISE_MAX_LINE];
+
+    if (fp == NULL) return -1;
+
+    while (fgets(buf,LINENOISE_MAX_LINE,fp) != NULL) {
+        char *p;
+
+        p = strchr(buf,'\r');
+        if (!p) p = strchr(buf,'\n');
+        if (p) *p = '\0';
+        linenoiseHistoryAdd(buf);
+    }
+    fclose(fp);
+    return 0;
+}
diff --git a/src/linenoise/linenoise.h b/src/linenoise/linenoise.h
new file mode 100644
index 000000000000..ed20232c576e
--- /dev/null
+++ b/src/linenoise/linenoise.h
@@ -0,0 +1,73 @@
+/* linenoise.h -- VERSION 1.0
+ *
+ * Guerrilla line editing library against the idea that a line editing lib
+ * needs to be 20,000 lines of C code.
+ *
+ * See linenoise.c for more information.
+ *
+ * ------------------------------------------------------------------------
+ *
+ * Copyright (c) 2010-2014, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *  *  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *  *  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __LINENOISE_H
+#define __LINENOISE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct linenoiseCompletions {
+  size_t len;
+  char **cvec;
+} linenoiseCompletions;
+
+typedef void(linenoiseCompletionCallback)(const char *, linenoiseCompletions *);
+typedef char*(linenoiseHintsCallback)(const char *, int *color, int *bold);
+typedef void(linenoiseFreeHintsCallback)(void *);
+void linenoiseSetCompletionCallback(linenoiseCompletionCallback *);
+void linenoiseSetHintsCallback(linenoiseHintsCallback *);
+void linenoiseSetFreeHintsCallback(linenoiseFreeHintsCallback *);
+void linenoiseAddCompletion(linenoiseCompletions *, const char *);
+
+char *linenoise(const char *prompt);
+void linenoiseFree(void *ptr);
+int linenoiseHistoryAdd(const char *line);
+int linenoiseHistorySetMaxLen(int len);
+int linenoiseHistorySave(const char *filename);
+int linenoiseHistoryLoad(const char *filename);
+void linenoiseClearScreen(void);
+void linenoiseSetMultiLine(int ml);
+void linenoisePrintKeyCodes(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LINENOISE_H */
diff --git a/src/nix-channel/nix-channel.cc b/src/nix-channel/nix-channel.cc
index 2aaae2f471b9..f2742bc3bbda 100755
--- a/src/nix-channel/nix-channel.cc
+++ b/src/nix-channel/nix-channel.cc
@@ -112,7 +112,6 @@ static void update(const StringSet & channelNames)
             // The URL doesn't unpack directly, so let's try treating it like a full channel folder with files in it
             // Check if the channel advertises a binary cache.
             DownloadRequest request(url + "/binary-cache-url");
-            request.showProgress = DownloadRequest::no;
             try {
                 auto dlRes = dl->download(request);
                 extraAttrs = "binaryCacheURL = \"" + *dlRes.data + "\";";
diff --git a/src/nix-daemon/nix-daemon.cc b/src/nix-daemon/nix-daemon.cc
index 1b90fad165af..44127635ded8 100644
--- a/src/nix-daemon/nix-daemon.cc
+++ b/src/nix-daemon/nix-daemon.cc
@@ -82,12 +82,7 @@ class TunnelLogger : public Logger
             defaultLogger->log(lvl, fs);
     }
 
-    void startActivity(Activity & activity, Verbosity lvl, const FormatOrString & fs) override
-    {
-        log(lvl, fs);
-    }
-
-    void stopActivity(Activity & activity) override
+    void event(const Event & ev) override
     {
     }
 };
@@ -621,6 +616,8 @@ static void performOp(ref<LocalStore> store, bool trusted, unsigned int clientVe
         from >> info.ca >> repair >> dontCheckSigs;
         if (!trusted && dontCheckSigs)
             dontCheckSigs = false;
+        if (!trusted)
+            info.ultimate = false;
 
         TeeSink tee(from);
         parseDump(tee, tee.source);
diff --git a/src/nix-env/nix-env.cc b/src/nix-env/nix-env.cc
index da39bf36ab65..464bcee4a848 100644
--- a/src/nix-env/nix-env.cc
+++ b/src/nix-env/nix-env.cc
@@ -989,7 +989,7 @@ static void opQuery(Globals & globals, Strings opFlags, Strings opArgs)
         try {
             if (i.hasFailed()) continue;
 
-            Activity act(*logger, lvlDebug, format("outputting query result ‘%1%’") % i.attrPath);
+            //Activity act(*logger, lvlDebug, format("outputting query result ‘%1%’") % i.attrPath);
 
             if (globals.prebuiltOnly &&
                 validPaths.find(i.queryOutPath()) == validPaths.end() &&
diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc
index c1b0b0ea092d..25f0b1bd692e 100644
--- a/src/nix-instantiate/nix-instantiate.cc
+++ b/src/nix-instantiate/nix-instantiate.cc
@@ -19,7 +19,7 @@ using namespace nix;
 
 static Expr * parseStdin(EvalState & state)
 {
-    Activity act(*logger, lvlTalkative, format("parsing standard input"));
+    //Activity act(*logger, lvlTalkative, format("parsing standard input"));
     return state.parseExprFromString(drainFD(0), absPath("."));
 }
 
diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index 4756fc44bba7..f23308b9bc30 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -223,9 +223,9 @@ PathSet InstallablesCommand::buildInstallables(ref<Store> store, bool dryRun)
         buildables.insert(b.begin(), b.end());
     }
 
-    printMissing(store, buildables);
-
-    if (!dryRun)
+    if (dryRun)
+        printMissing(store, buildables);
+    else
         store->buildPaths(buildables);
 
     PathSet outPaths;
diff --git a/src/nix/local.mk b/src/nix/local.mk
index e71cf16fabf6..c7d2d328aab5 100644
--- a/src/nix/local.mk
+++ b/src/nix/local.mk
@@ -2,12 +2,8 @@ programs += nix
 
 nix_DIR := $(d)
 
-nix_SOURCES := $(wildcard $(d)/*.cc)
+nix_SOURCES := $(wildcard $(d)/*.cc) src/linenoise/linenoise.c
 
 nix_LIBS = libexpr libmain libstore libutil libformat
 
-ifeq ($(HAVE_READLINE), 1)
-  nix_LDFLAGS += -lreadline
-endif
-
 $(eval $(call install-symlink, nix, $(bindir)/nix-hash))
diff --git a/src/nix/ls.cc b/src/nix/ls.cc
index 3476dfb05287..417b7b421b1c 100644
--- a/src/nix/ls.cc
+++ b/src/nix/ls.cc
@@ -61,6 +61,10 @@ struct MixLs : virtual Args
                 showFile(curPath, relPath);
         };
 
+        if (path == "/") {
+            path = "";
+        }
+
         auto st = accessor->stat(path);
         if (st.type == FSAccessor::Type::tMissing)
             throw Error(format("path ‘%1%’ does not exist") % path);
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 440ced97dfcc..216f0bccef11 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -27,6 +27,7 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
 
 void mainWrapped(int argc, char * * argv)
 {
+    verbosity = lvlError;
     settings.verboseBuild = false;
 
     initNix();
diff --git a/src/nix/progress-bar.cc b/src/nix/progress-bar.cc
index 69811b282804..24e435f81e8b 100644
--- a/src/nix/progress-bar.cc
+++ b/src/nix/progress-bar.cc
@@ -1,8 +1,12 @@
 #include "progress-bar.hh"
 #include "util.hh"
 #include "sync.hh"
+#include "store-api.hh"
 
 #include <map>
+#include <atomic>
+
+#include <sys/ioctl.h>
 
 namespace nix {
 
@@ -12,31 +16,47 @@ private:
 
     struct ActInfo
     {
-        Activity * activity;
-        Verbosity lvl;
-        std::string s;
+        std::string s, s2;
     };
 
-    struct Progress
+    struct DownloadInfo
     {
-        uint64_t expected = 0, progress = 0;
+        std::string uri;
+        uint64_t current = 0;
+        uint64_t expected = 0;
     };
 
     struct State
     {
+        std::map<Activity::t, Path> builds;
+        std::set<Activity::t> runningBuilds;
+        uint64_t succeededBuilds = 0;
+        uint64_t failedBuilds = 0;
+        std::map<Activity::t, Path> substitutions;
+        std::set<Activity::t> runningSubstitutions;
+        uint64_t succeededSubstitutions = 0;
+        uint64_t downloadedBytes = 0; // finished downloads
+        std::map<Activity::t, DownloadInfo> downloads;
         std::list<ActInfo> activities;
-        std::map<Activity *, std::list<ActInfo>::iterator> its;
-        std::map<std::string, Progress> progress;
+        std::map<Activity::t, std::list<ActInfo>::iterator> its;
     };
 
     Sync<State> state_;
 
+    int width = 0;
+
 public:
 
+    ProgressBar()
+    {
+        struct winsize ws;
+        if (ioctl(1, TIOCGWINSZ, &ws) == 0)
+            width = ws.ws_col;
+    }
+
     ~ProgressBar()
     {
         auto state(state_.lock());
-        assert(state->activities.empty());
         writeToStderr("\r\e[K");
     }
 
@@ -52,52 +72,36 @@ public:
         update(state);
     }
 
-    void startActivity(Activity & activity, Verbosity lvl, const FormatOrString & fs) override
-    {
-        if (lvl > verbosity) return;
-        auto state(state_.lock());
-        state->activities.emplace_back(ActInfo{&activity, lvl, fs.s});
-        state->its.emplace(&activity, std::prev(state->activities.end()));
-        update(*state);
-    }
-
-    void stopActivity(Activity & activity) override
-    {
-        auto state(state_.lock());
-        auto i = state->its.find(&activity);
-        if (i == state->its.end()) return;
-        state->activities.erase(i->second);
-        state->its.erase(i);
-        update(*state);
-    }
-
-    void setExpected(const std::string & label, uint64_t value) override
+    void createActivity(State & state, Activity::t activity, const std::string & s)
     {
-        auto state(state_.lock());
-        state->progress[label].expected = value;
-    }
-
-    void setProgress(const std::string & label, uint64_t value) override
-    {
-        auto state(state_.lock());
-        state->progress[label].progress = value;
+        state.activities.emplace_back(ActInfo{s});
+        state.its.emplace(activity, std::prev(state.activities.end()));
     }
 
-    void incExpected(const std::string & label, uint64_t value) override
+    void deleteActivity(State & state, Activity::t activity)
     {
-        auto state(state_.lock());
-        state->progress[label].expected += value;
+        auto i = state.its.find(activity);
+        if (i != state.its.end()) {
+            state.activities.erase(i->second);
+            state.its.erase(i);
+        }
     }
 
-    void incProgress(const std::string & label, uint64_t value) override
+    void updateActivity(State & state, Activity::t activity, const std::string & s2)
     {
-        auto state(state_.lock());
-        state->progress[label].progress += value;
+        auto i = state.its.find(activity);
+        assert(i != state.its.end());
+        ActInfo info = *i->second;
+        state.activities.erase(i->second);
+        info.s2 = s2;
+        state.activities.emplace_back(info);
+        i->second = std::prev(state.activities.end());
     }
 
     void update()
     {
         auto state(state_.lock());
+        update(*state);
     }
 
     void update(State & state)
@@ -113,28 +117,169 @@ public:
 
         if (!state.activities.empty()) {
             if (!status.empty()) line += " ";
-            line += state.activities.rbegin()->s;
+            auto i = state.activities.rbegin();
+            line += i->s;
+            if (!i->s2.empty()) {
+                line += ": ";
+                line += i->s2;
+            }
         }
 
         line += "\e[K";
-        writeToStderr(line);
+        writeToStderr(std::string(line, 0, width - 1));
     }
 
     std::string getStatus(State & state)
     {
         std::string res;
-        for (auto & p : state.progress)
-            if (p.second.expected || p.second.progress) {
-                if (!res.empty()) res += ", ";
-                res += std::to_string(p.second.progress);
-                if (p.second.expected) {
-                    res += "/";
-                    res += std::to_string(p.second.expected);
-                }
-                res += " "; res += p.first;
+
+        if (state.failedBuilds) {
+            if (!res.empty()) res += ", ";
+            res += fmt(ANSI_RED "%d failed" ANSI_NORMAL, state.failedBuilds);
+        }
+
+        if (!state.builds.empty() || state.succeededBuilds)
+        {
+            if (!res.empty()) res += ", ";
+            if (!state.runningBuilds.empty())
+                res += fmt(ANSI_BLUE "%d" "/" ANSI_NORMAL, state.runningBuilds.size());
+            res += fmt(ANSI_GREEN "%d/%d built" ANSI_NORMAL,
+                state.succeededBuilds, state.succeededBuilds + state.builds.size());
+        }
+
+        if (!state.substitutions.empty() || state.succeededSubstitutions) {
+            if (!res.empty()) res += ", ";
+            if (!state.runningSubstitutions.empty())
+                res += fmt(ANSI_BLUE "%d" "/" ANSI_NORMAL, state.runningSubstitutions.size());
+            res += fmt(ANSI_GREEN "%d/%d fetched" ANSI_NORMAL,
+                state.succeededSubstitutions,
+                state.succeededSubstitutions + state.substitutions.size());
+        }
+
+        if (!state.downloads.empty() || state.downloadedBytes) {
+            if (!res.empty()) res += ", ";
+            uint64_t expected = state.downloadedBytes, current = state.downloadedBytes;
+            for (auto & i : state.downloads) {
+                expected += i.second.expected;
+                current += i.second.current;
             }
+            res += fmt("%1$.0f/%2$.0f KiB", current / 1024.0, expected / 1024.0);
+        }
+
         return res;
     }
+
+    void event(const Event & ev) override
+    {
+        if (ev.type == evBuildCreated) {
+            auto state(state_.lock());
+            state->builds[ev.getI(0)] = ev.getS(1);
+            update(*state);
+        }
+
+        if (ev.type == evBuildStarted) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            state->runningBuilds.insert(act);
+            auto name = storePathToName(state->builds[act]);
+            if (hasSuffix(name, ".drv"))
+                name.resize(name.size() - 4);
+            createActivity(*state, act, fmt("building " ANSI_BOLD "%s" ANSI_NORMAL, name));
+            update(*state);
+        }
+
+        if (ev.type == evBuildFinished) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            if (ev.getI(1)) {
+                if (state->runningBuilds.count(act))
+                    state->succeededBuilds++;
+            } else
+                state->failedBuilds++;
+            state->runningBuilds.erase(act);
+            state->builds.erase(act);
+            deleteActivity(*state, act);
+            update(*state);
+        }
+
+        if (ev.type == evBuildOutput) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            assert(state->runningBuilds.count(act));
+            updateActivity(*state, act, ev.getS(1));
+            update(*state);
+        }
+
+        if (ev.type == evSubstitutionCreated) {
+            auto state(state_.lock());
+            state->substitutions[ev.getI(0)] = ev.getS(1);
+            update(*state);
+        }
+
+        if (ev.type == evSubstitutionStarted) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            state->runningSubstitutions.insert(act);
+            auto name = storePathToName(state->substitutions[act]);
+            createActivity(*state, act, fmt("fetching " ANSI_BOLD "%s" ANSI_NORMAL, name));
+            update(*state);
+        }
+
+        if (ev.type == evSubstitutionFinished) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            if (ev.getI(1)) {
+                if (state->runningSubstitutions.count(act))
+                    state->succeededSubstitutions++;
+            }
+            state->runningSubstitutions.erase(act);
+            state->substitutions.erase(act);
+            deleteActivity(*state, act);
+            update(*state);
+        }
+
+        if (ev.type == evDownloadCreated) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            std::string uri = ev.getS(1);
+            state->downloads.emplace(act, DownloadInfo{uri});
+            if (state->runningSubstitutions.empty()) // FIXME: hack
+                createActivity(*state, act, fmt("downloading " ANSI_BOLD "%s" ANSI_NORMAL "", uri));
+            update(*state);
+        }
+
+        if (ev.type == evDownloadProgress) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            auto i = state->downloads.find(act);
+            assert(i != state->downloads.end());
+            i->second.expected = ev.getI(1);
+            i->second.current = ev.getI(2);
+            update(*state);
+        }
+
+        if (ev.type == evDownloadSucceeded) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            auto i = state->downloads.find(act);
+            assert(i != state->downloads.end());
+            state->downloadedBytes += ev.getI(1);
+            state->downloads.erase(i);
+            deleteActivity(*state, act);
+            update(*state);
+        }
+
+        if (ev.type == evDownloadDestroyed) {
+            auto state(state_.lock());
+            Activity::t act = ev.getI(0);
+            auto i = state->downloads.find(act);
+            if (i != state->downloads.end()) {
+                state->downloads.erase(i);
+                deleteActivity(*state, act);
+                update(*state);
+            }
+        }
+    }
 };
 
 StartProgressBar::StartProgressBar()
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index 13488bf1dbd4..437c7903ed40 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -1,13 +1,8 @@
-#if HAVE_LIBREADLINE
-
 #include <iostream>
 #include <cstdlib>
 
 #include <setjmp.h>
 
-#include <readline/readline.h>
-#include <readline/history.h>
-
 #include "shared.hh"
 #include "eval.hh"
 #include "eval-inline.hh"
@@ -18,6 +13,9 @@
 #include "affinity.hh"
 #include "globals.hh"
 #include "command.hh"
+#include "finally.hh"
+
+#include "src/linenoise/linenoise.h"
 
 namespace nix {
 
@@ -44,14 +42,11 @@ struct NixRepl
 
     const Path historyFile;
 
-    StringSet completions;
-    StringSet::iterator curCompletion;
-
     NixRepl(const Strings & searchPath, nix::ref<Store> store);
     ~NixRepl();
     void mainLoop(const Strings & files);
-    void completePrefix(string prefix);
-    bool getLine(string & input, const char * prompt);
+    StringSet completePrefix(string prefix);
+    bool getLine(string & input, const std::string &prompt);
     Path getDerivationPath(Value & v);
     bool processLine(string line);
     void loadFile(const Path & path);
@@ -122,7 +117,17 @@ NixRepl::NixRepl(const Strings & searchPath, nix::ref<Store> store)
 
 NixRepl::~NixRepl()
 {
-    write_history(historyFile.c_str());
+    linenoiseHistorySave(historyFile.c_str());
+}
+
+
+static NixRepl * curRepl; // ugly
+
+static void completionCallback(const char * s, linenoiseCompletions *lc)
+{
+    /* Otherwise, return all symbols that start with the prefix. */
+    for (auto & c : curRepl->completePrefix(s))
+        linenoiseAddCompletion(lc, c.c_str());
 }
 
 
@@ -137,22 +142,20 @@ void NixRepl::mainLoop(const Strings & files)
     reloadFiles();
     if (!loadedFiles.empty()) std::cout << std::endl;
 
-    // Allow nix-repl specific settings in .inputrc
-    rl_readline_name = "nix-repl";
-    using_history();
     createDirs(dirOf(historyFile));
-    read_history(historyFile.c_str());
+    linenoiseHistorySetMaxLen(1000);
+    linenoiseHistoryLoad(historyFile.c_str());
 
-    string input;
+    curRepl = this;
+    linenoiseSetCompletionCallback(completionCallback);
+
+    std::string input;
 
     while (true) {
         // When continuing input from previous lines, don't print a prompt, just align to the same
         // number of chars as the prompt.
-        const char * prompt = input.empty() ? "nix-repl> " : "          ";
-        if (!getLine(input, prompt)) {
-            std::cout << std::endl;
+        if (!getLine(input, input.empty() ? "nix-repl> " : "          "))
             break;
-        }
 
         try {
             if (!removeWhitespace(input).empty() && !processLine(input)) return;
@@ -170,103 +173,57 @@ void NixRepl::mainLoop(const Strings & files)
             printMsg(lvlError, format(error + "%1%%2%") % (settings.showTrace ? e.prefix() : "") % e.msg());
         }
 
-        // We handled the current input fully, so we should clear it and read brand new input.
+        // We handled the current input fully, so we should clear it
+        // and read brand new input.
+        linenoiseHistoryAdd(input.c_str());
         input.clear();
         std::cout << std::endl;
     }
 }
 
 
-/* Apparently, the only way to get readline() to return on Ctrl-C
-   (SIGINT) is to use siglongjmp().  That's fucked up... */
-static sigjmp_buf sigintJmpBuf;
-
-
-static void sigintHandler(int signo)
+bool NixRepl::getLine(string & input, const std::string &prompt)
 {
-    siglongjmp(sigintJmpBuf, 1);
-}
-
-
-/* Oh, if only g++ had nested functions... */
-NixRepl * curRepl;
-
-char * completerThunk(const char * s, int state)
-{
-    string prefix(s);
-
-    /* If the prefix has a slash in it, use readline's builtin filename
-       completer. */
-    if (prefix.find('/') != string::npos)
-        return rl_filename_completion_function(s, state);
-
-    /* Otherwise, return all symbols that start with the prefix. */
-    if (state == 0) {
-        curRepl->completePrefix(s);
-        curRepl->curCompletion = curRepl->completions.begin();
-    }
-    if (curRepl->curCompletion == curRepl->completions.end()) return 0;
-    return strdup((curRepl->curCompletion++)->c_str());
+    char * s = linenoise(prompt.c_str());
+    Finally doFree([&]() { linenoiseFree(s); });
+    if (!s) return false;
+    input += s;
+    return true;
 }
 
 
-bool NixRepl::getLine(string & input, const char * prompt)
+StringSet NixRepl::completePrefix(string prefix)
 {
-    struct sigaction act, old;
-    act.sa_handler = sigintHandler;
-    sigfillset(&act.sa_mask);
-    act.sa_flags = 0;
-    if (sigaction(SIGINT, &act, &old))
-        throw SysError("installing handler for SIGINT");
-
-    static sigset_t savedSignalMask, set;
-    sigemptyset(&set);
-    sigaddset(&set, SIGINT);
-
-    if (sigprocmask(SIG_UNBLOCK, &set, &savedSignalMask))
-        throw SysError("unblocking SIGINT");
+    StringSet completions;
 
-    if (sigsetjmp(sigintJmpBuf, 1)) {
-        input.clear();
+    size_t start = prefix.find_last_of(" \n\r\t(){}[]");
+    std::string prev, cur;
+    if (start == std::string::npos) {
+        prev = "";
+        cur = prefix;
     } else {
-        curRepl = this;
-        rl_completion_entry_function = completerThunk;
-
-        char * s = readline(prompt);
-        if (!s) return false;
-        input.append(s);
-        input.push_back('\n');
-        if (!removeWhitespace(s).empty()) {
-            add_history(s);
-            append_history(1, 0);
-        }
-        free(s);
+        prev = std::string(prefix, 0, start + 1);
+        cur = std::string(prefix, start + 1);
     }
 
-    _isInterrupted = 0;
-
-    if (sigprocmask(SIG_SETMASK, &savedSignalMask, nullptr))
-        throw SysError("restoring signals");
-
-    if (sigaction(SIGINT, &old, 0))
-        throw SysError("restoring handler for SIGINT");
-
-    return true;
-}
-
-
-void NixRepl::completePrefix(string prefix)
-{
-    completions.clear();
-
-    size_t dot = prefix.rfind('.');
+    size_t slash, dot;
 
-    if (dot == string::npos) {
+    if ((slash = cur.rfind('/')) != string::npos) {
+        try {
+            auto dir = std::string(cur, 0, slash);
+            auto prefix2 = std::string(cur, slash + 1);
+            for (auto & entry : readDirectory(dir == "" ? "/" : dir)) {
+                if (entry.name[0] != '.' && hasPrefix(entry.name, prefix2))
+                    completions.insert(prev + dir + "/" + entry.name);
+            }
+        } catch (Error &) {
+        }
+    } else if ((dot = cur.rfind('.')) == string::npos) {
         /* This is a variable name; look it up in the current scope. */
-        StringSet::iterator i = varNames.lower_bound(prefix);
+        StringSet::iterator i = varNames.lower_bound(cur);
         while (i != varNames.end()) {
-            if (string(*i, 0, prefix.size()) != prefix) break;
-            completions.insert(*i);
+            if (string(*i, 0, cur.size()) != cur) break;
+            completions.insert(prev + *i);
             i++;
         }
     } else {
@@ -274,8 +231,8 @@ void NixRepl::completePrefix(string prefix)
             /* This is an expression that should evaluate to an
                attribute set.  Evaluate it to get the names of the
                attributes. */
-            string expr(prefix, 0, dot);
-            string prefix2 = string(prefix, dot + 1);
+            string expr(cur, 0, dot);
+            string cur2 = string(cur, dot + 1);
 
             Expr * e = parseString(expr);
             Value v;
@@ -284,8 +241,8 @@ void NixRepl::completePrefix(string prefix)
 
             for (auto & i : *v.attrs) {
                 string name = i.name;
-                if (string(name, 0, prefix2.size()) != prefix2) continue;
-                completions.insert(expr + "." + name);
+                if (string(name, 0, cur2.size()) != cur2) continue;
+                completions.insert(prev + expr + "." + name);
             }
 
         } catch (ParseError & e) {
@@ -296,6 +253,8 @@ void NixRepl::completePrefix(string prefix)
             // Quietly ignore undefined variable errors.
         }
     }
+
+    return completions;
 }
 
 
@@ -728,5 +687,3 @@ struct CmdRepl : StoreCommand
 static RegisterCommand r1(make_ref<CmdRepl>());
 
 }
-
-#endif
diff --git a/src/nix/sigs.cc b/src/nix/sigs.cc
index d8d8c0f53df0..3dd03771619f 100644
--- a/src/nix/sigs.cc
+++ b/src/nix/sigs.cc
@@ -42,10 +42,10 @@ struct CmdCopySigs : StorePathsCommand
         std::string doneLabel = "done";
         std::atomic<size_t> added{0};
 
-        logger->setExpected(doneLabel, storePaths.size());
+        //logger->setExpected(doneLabel, storePaths.size());
 
         auto doPath = [&](const Path & storePath) {
-            Activity act(*logger, lvlInfo, format("getting signatures for ‘%s’") % storePath);
+            //Activity act(*logger, lvlInfo, format("getting signatures for ‘%s’") % storePath);
 
             checkInterrupt();
 
@@ -76,7 +76,7 @@ struct CmdCopySigs : StorePathsCommand
                 added += newSigs.size();
             }
 
-            logger->incProgress(doneLabel);
+            //logger->incProgress(doneLabel);
         };
 
         for (auto & storePath : storePaths)
diff --git a/src/nix/verify.cc b/src/nix/verify.cc
index 2f8d02fa060e..8facb4bef8a2 100644
--- a/src/nix/verify.cc
+++ b/src/nix/verify.cc
@@ -65,7 +65,7 @@ struct CmdVerify : StorePathsCommand
         std::string untrustedLabel("untrusted");
         std::string corruptedLabel("corrupted");
         std::string failedLabel("failed");
-        logger->setExpected(doneLabel, storePaths.size());
+        //logger->setExpected(doneLabel, storePaths.size());
 
         ThreadPool pool;
 
@@ -73,7 +73,7 @@ struct CmdVerify : StorePathsCommand
             try {
                 checkInterrupt();
 
-                Activity act(*logger, lvlInfo, format("checking ‘%s’") % storePath);
+                //Activity act(*logger, lvlInfo, format("checking ‘%s’") % storePath);
 
                 auto info = store->queryPathInfo(storePath);
 
@@ -85,7 +85,7 @@ struct CmdVerify : StorePathsCommand
                     auto hash = sink.finish();
 
                     if (hash.first != info->narHash) {
-                        logger->incProgress(corruptedLabel);
+                        //logger->incProgress(corruptedLabel);
                         corrupted = 1;
                         printError(
                             format("path ‘%s’ was modified! expected hash ‘%s’, got ‘%s’")
@@ -137,19 +137,19 @@ struct CmdVerify : StorePathsCommand
                     }
 
                     if (!good) {
-                        logger->incProgress(untrustedLabel);
+                        //logger->incProgress(untrustedLabel);
                         untrusted++;
                         printError(format("path ‘%s’ is untrusted") % info->path);
                     }
 
                 }
 
-                logger->incProgress(doneLabel);
+                //logger->incProgress(doneLabel);
                 done++;
 
             } catch (Error & e) {
                 printError(format(ANSI_RED "error:" ANSI_NORMAL " %s") % e.what());
-                logger->incProgress(failedLabel);
+                //logger->incProgress(failedLabel);
                 failed++;
             }
         };
diff --git a/tests/lang/eval-okay-regex-match.nix b/tests/lang/eval-okay-regex-match.nix
index ae6501532d11..273e2590713e 100644
--- a/tests/lang/eval-okay-regex-match.nix
+++ b/tests/lang/eval-okay-regex-match.nix
@@ -17,8 +17,11 @@ assert  matches "fo+" "foo";
 assert  matches "fo{1,2}" "foo";
 assert !matches "fo{1,2}" "fooo";
 assert !matches "fo*" "foobar";
+assert  matches "[[:space:]]+([^[:space:]]+)[[:space:]]+" "  foo   ";
+assert !matches "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  foo   ";
 
 assert match "(.*)\\.nix" "foobar.nix" == [ "foobar" ];
+assert match "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  FOO   " == [ "FOO" ];
 
 assert splitFN "/path/to/foobar.nix" == [ "/path/to/" "/path/to" "foobar" "nix" ];
 assert splitFN "foobar.cc" == [ null null "foobar" "cc" ];
diff --git a/tests/local.mk b/tests/local.mk
index 108e3febdb0c..7d99a0fc7675 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -13,7 +13,8 @@ nix_tests = \
   check-reqs.sh pass-as-file.sh tarball.sh restricted.sh \
   placeholders.sh nix-shell.sh \
   linux-sandbox.sh \
-  build-remote.sh
+  build-remote.sh \
+  nar-index.sh
   # parallel.sh
 
 install-tests += $(foreach x, $(nix_tests), tests/$(x))
diff --git a/tests/nar-index.nix b/tests/nar-index.nix
new file mode 100644
index 000000000000..0e2a7f721135
--- /dev/null
+++ b/tests/nar-index.nix
@@ -0,0 +1,23 @@
+with import ./config.nix;
+
+rec {
+    a = mkDerivation {
+        name = "nar-index-a";
+        builder = builtins.toFile "builder.sh"
+      ''
+        mkdir $out
+        mkdir $out/foo
+        touch $out/foo-x
+        touch $out/foo/bar
+        touch $out/foo/baz
+        touch $out/qux
+        mkdir $out/zyx
+
+        cat >$out/foo/data <<EOF
+        lasjdöaxnasd
+asdom 12398
+ä"§Æẞ¢«»”alsd
+EOF
+      '';
+    };
+}
\ No newline at end of file
diff --git a/tests/nar-index.sh b/tests/nar-index.sh
new file mode 100644
index 000000000000..51369346c88a
--- /dev/null
+++ b/tests/nar-index.sh
@@ -0,0 +1,23 @@
+source common.sh
+
+echo "building test path"
+storePath="$(nix-build nar-index.nix -A a --no-out-link)"
+
+cd "$TEST_ROOT"
+
+echo "dumping path to nar"
+narFile="$TEST_ROOT/path.nar"
+nix-store --dump $storePath > $narFile
+
+echo "check that find and ls-nar match"
+( cd $storePath; find . | sort ) > files.find
+nix ls-nar -R -d $narFile "" | sort > files.ls-nar
+diff -u files.find files.ls-nar
+
+echo "check that file contents of data match"
+nix cat-nar $narFile /foo/data > data.cat-nar
+diff -u data.cat-nar $storePath/foo/data
+
+echo "check that file contents of baz match"
+nix cat-nar $narFile /foo/baz > baz.cat-nar
+diff -u baz.cat-nar $storePath/foo/baz
\ No newline at end of file