git gsr

git-gsr

#!/bin/sh

usage () {
    cat >&2 <<'__USAGE__'
usage: git gsr [-P | --perl-regexp] <old> <new> [paths...]

  replace all occurrances of <old> with <new> optionally limited to
  <paths...> (as interpreted by git grep)

  -P, --perl-regexp     interpret <old> as perl regular expression;
                        default is to treat it as a fixed string.

__USAGE__
    exit 1
}

pattern='-F'
perl='BEGIN {($old, $new) = (shift, shift)} s/\Q$old\E/$new/g'

case "$1" in
    -P|--perl-regexp)
        shift
        pattern='-P'
        perl='BEGIN {($old, $new) = (shift, shift)} s/$old/$new/g'
        ;;
    -*) usage
        ;;
esac
test $# -lt 2 && usage
old=$1; new=$2; shift; shift
git grep -l -z $pattern "$old" -- "$@" |
xargs -0 perl -pi -e "$perl" "$old" "$new"