When ‘--help’ is given, just run ‘man’ to show the manual page

I.e. do what git does.  I'm too lazy to keep the builtin help text up
to date :-)

Also add ‘--help’ to various commands that lacked it
(e.g. nix-collect-garbage).

1 files changed, 1 insertions, 2 deletions

diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc
index 34f81b14a286..4d8f43507ca7 100644
--- a/src/nix-instantiate/nix-instantiate.cc
+++ b/src/nix-instantiate/nix-instantiate.cc
@@ -8,7 +8,6 @@
 #include "util.hh"
 #include "store-api.hh"
 #include "common-opts.hh"
-#include "help.txt.hh"
 
 #include <map>
 #include <iostream>
@@ -19,7 +18,7 @@ using namespace nix;
 
 void printHelp()
 {
-    std::cout << string((char *) helpText);
+    showManPage("nix-instantiate");
 }