git-wrapper

#!/bin/sh

:<<'=cut'

=head1 NAME

git-wrapper - avoid committing as you@invalid

=head1 SYNOPSIS

    alias git=git-wrapper

=head1 DESCRIPTION

Use this instead of the real B<git>
to protect yourself against committing stuff
with the wrong identity.

This requires that you do not configure a global
C<user.email> value at all.
Unless your user name and host name
happen to be a really unlucky combination
which is equivalent to what you actually
want to use,
the default value will be unacceptable,
which this wrapper traps before it
chains to the real B<git>
for anything except F<git config>
(so you can set up your C<user.email>
to what you want it to be in each
individual check-out)
and F<git clone>
(so you can clone :-)
and F<git init>.

=head1 INSTALLATION

    alias git=git-wrapper

Add this to your F<.bash_profile> or similar to use globally.

=head1 HISTORY

I like to use different identities on different Git projects.
Inevitably, I ended up committing stuff with the wrong identity
more often than not (and needing to run the script I created
out of L<http://stackoverflow.com/a/870367/874188> all the time),
so I felt I had to come up with a fix.  I played around with
Git aliases for a bit, but in the end, this turned out to be
the simplest and most usable solution.

=head1 AUTHOR

era eriksson
L<era+github@iki.fi>

=head1 LICENSE

Creative Commons CC-SA

=cut


compare_emails () {
    local global # sic
    local local  # sac
    global=$(cd; git config user.email)
    local=$(git config user.email)
    case $global in $local)
            echo "$0: user.email '$global' is also local -- abort" >&2
	    return 55 ;;
    esac
    return 0
}

case $1 in
    config | clone | init | --help | -h ) ;;
    *)      compare_emails || exit $?;;
esac

exec git "$@";