This means that you can take a tag object, and do
git-cat-file commit tagname
and it will cat the commit that the tag points to. Or you can
cat the tree that a commit (or tag) points to.
It still gives the old behaviour if you just give it the
original type, ie if you want to see the tag object itself,
you'd do
git-cat-file -t tagname
and you'd get the expected tag output.
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.
