remove #!interpreter line from shell libraries

In a shell snippet meant to be sourced by other shell scripts, an opening #! line does more harm than good. The harm: - When the shell library is sourced, the interpreter and options from the #! line are not used. Specifying a particular shell can confuse the reader into thinking it is safe for the shell library to rely on idiosyncrasies of that shell. - Using #! instead of a plain comment drops a helpful visual clue that this is a shell library and not a self-contained script. - Tools such as lintian can use a #! line to tell when an installation script has failed by forgetting to set a script executable. This check does not work if shell libraries also start with a #! line. The good: - Text editors notice the #! line and use it for syntax highlighting if you try to edit the installed scripts (without ".sh" suffix) in place. The use of the #! for file type detection is not needed because Git's shell libraries are meant to be edited in source form (with ".sh" suffix). Replace the opening #! lines with comments. This involves tweaking the test harness's valgrind support to find shell libraries by looking for "# " in the first line instead of "#!" (see v1.7.6-rc3~7, 2011-06-17). Suggested by Russ Allbery through lintian. Thanks to Jeff King and Clemens Buchacher for further analysis. Tested by searching for non-executable scripts with #! line: find . -name .git -prune -o -type f -not -executable | while read file do read line <"$file" case $line in '#!'*) echo "$file" ;; esac done The only remaining scripts found are templates for shell scripts (unimplemented.sh, wrap-for-bin.sh) and sample input used in tests (t/t4034/perl/{pre,post}). Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>