This allows the programs to use various simplified versions of
the SHA1 names, eg just say "HEAD" for the SHA1 pointed to by
the .git/HEAD file etc.
For example, this commit has been done with
git-commit-tree $(git-write-tree) -p HEAD
instead of the traditional "$(cat .git/HEAD)" syntax.
Now there is error() for "library" errors and die() for fatal "application"
errors. usage() is now used strictly only for usage errors.
Signed-off-by: Petr Baudis <pasky@ucw.cz>
The tool interface sucks (especially "committing" information, which is just
me doing everything by hand from the command line), but I think this is in
theory actually a viable way of describing the world. So copyright it.