1 files changed, 74 insertions, 0 deletions
diff --git a/src/nix/cat.cc b/src/nix/cat.cc
new file mode 100644
index 000000000000..2405a8cb44ef
--- /dev/null
+++ b/src/nix/cat.cc
@@ -0,0 +1,74 @@
+#include "command.hh"
+#include "store-api.hh"
+#include "fs-accessor.hh"
+#include "nar-accessor.hh"
+
+using namespace nix;
+
+struct MixCat : virtual Args
+{
+    std::string path;
+
+    void cat(ref<FSAccessor> accessor)
+    {
+        auto st = accessor->stat(path);
+        if (st.type == FSAccessor::Type::tMissing)
+            throw Error(format("path ‘%1%’ does not exist") % path);
+        if (st.type != FSAccessor::Type::tRegular)
+            throw Error(format("path ‘%1%’ is not a regular file") % path);
+
+        std::cout << accessor->readFile(path);
+    }
+};
+
+struct CmdCatStore : StoreCommand, MixCat
+{
+    CmdCatStore()
+    {
+        expectArg("path", &path);
+    }
+
+    std::string name() override
+    {
+        return "cat-store";
+    }
+
+    std::string description() override
+    {
+        return "print the contents of a store file on stdout";
+    }
+
+    void run(ref<Store> store) override
+    {
+        cat(store->getFSAccessor());
+    }
+};
+
+struct CmdCatNar : StoreCommand, MixCat
+{
+    Path narPath;
+
+    CmdCatNar()
+    {
+        expectArg("nar", &narPath);
+        expectArg("path", &path);
+    }
+
+    std::string name() override
+    {
+        return "cat-nar";
+    }
+
+    std::string description() override
+    {
+        return "print the contents of a file inside a NAR file";
+    }
+
+    void run(ref<Store> store) override
+    {
+        cat(makeNarAccessor(make_ref<std::string>(readFile(narPath))));
+    }
+};
+
+static RegisterCommand r1(make_ref<CmdCatStore>());
+static RegisterCommand r2(make_ref<CmdCatNar>());