* Help text for all (non-script) programs, so no more:

$ nix-instantiate --help
error: unknown flag `--help`
Try `nix-instantiate --help' for more information.

:-)

src/nix-env/Makefile.am

@@ -6,6 +6,11 @@ nix_env_LDADD = ../libmain/libmain.a ../libexpr/libexpr.a \
  ../boost/format/libformat.a -L../../externals/inst/lib -ldb_cxx \
  -lsglr -lATB -lconversion -lasfix2 -lmept -lATerm
 
+main.o: help.txt.hh
+
+%.txt.hh: %.txt
+	../bin2c/bin2c helpText < $< > $@ || (rm $@ && exit 1)
+
 AM_CXXFLAGS = \
  -I.. -I../../externals/inst/include -I../libutil -I../libstore \
  -I../libexpr -I../libmain

src/nix-env/help.txt

@@ -0,0 +1,31 @@
+nix-env [OPTIONS...] [ARGUMENTS...]
+
+`nix-env' is a tool to manipulate Nix user environments.
+
+Operations:
+
+  --install / -i FILE: add a derivation to the user environment
+  --uninstall / -u: remove a derivation to the user environment
+  --query / -q: perform a query on an environment or Nix expression
+
+The previous operations take a list of derivation names.  The special
+name `*' may be used to indicate all derivations.
+
+  --version: output version information
+  --help: display help
+
+Query types:
+
+  --name: print derivation names (default)
+  --expr / -e: print derivation store expression
+  --status / -s: print installed/present status
+
+Query sources:
+
+  --installed: use installed derivations (default)
+  --available / -f FILE: use derivations available in expression FILE
+
+Options:
+
+  --verbose / -v: verbose operation (may be repeated)
+  --keep-failed / -K: keep temporary directories of failed builds

src/nix-env/main.cc

@@ -3,6 +3,7 @@
 #include "shared.hh"
 #include "parser.hh"
 #include "eval.hh"
+#include "help.txt.hh"
 
 
 typedef void (* Operation) (EvalState & state,
@@ -20,6 +21,12 @@ struct DrvInfo
 typedef map<Path, DrvInfo> DrvInfos;
 
 
+void printHelp()
+{
+    cout << string((char *) helpText, sizeof helpText);
+}
+
+
 bool parseDerivation(EvalState & state, Expr e, DrvInfo & drv)
 {
     ATMatcher m;
@@ -395,10 +402,6 @@ void run(Strings args)
             op = opUninstall;
         else if (arg == "--query" || arg == "-q")
             op = opQuery;
-        else if (arg == "--verbose" || arg == "-v")
-            verbosity = (Verbosity) ((int) verbosity + 1);
-        else if (arg[0] == '-')
-            opFlags.push_back(arg);
         else
             opArgs.push_back(arg);