git sed s%pattern%replacement%flags [-- git-grep flags]

func.ged.sh

#!/bin/bash

ged() {
    local sprf="$1" ; shift
    [[ "$sprf" == 's%'* ]] || return 10  # MUST be s%p%r%f
    local p="$(echo "$sprf" | cut -d% -f2)"
    [[ "$p" == '' ]] && return 11
    if git status --porcelain | grep '^ ' | grep .; then return 12; fi
    local git_grep='git grep -IE'
    local f="$(echo "$sprf" | cut -d% -f4)"
    [[ "$f" == *'i'* ]] && local git_grep="$git_grep -i"
    $git_grep --files-with-matches --null "$p" $@ | xargs --null --no-run-if-empty sed -i "$sprf"
}