Git 管理下のファイルを一括置換する git-sed コマンドを作った ref: https://qiita.com/tonluqclml/items/13b323cea92425b85218

file0.txt

$ git ls-files | xargs -n 1 sed -i 's|find_by_admin|find_by(type: :admin)|g'

file1.txt

$ git sed 's|find_by_admin|find_by(type: :admin)|g'

file2.txt

$ git sed 's|find_by_admin|find_by(type: :admin)|g' spec/ test/

file3.txt

#!/bin/bash
set -euC
if [ "$#" -eq 0 ]; then
  echo 'git sed COMMAND [PATH [PATH[...]]]' >&2
  exit 1
fi

if which gsed > /dev/null; then
  SED=gsed # for macOS
else
  SED=sed
fi

CMD=(-e "$1")
shift

apply_sed() {
  f="$1"
}

while read -r f; do
  [ -f "$f" ] && [ ! -L "$f" ] && "$SED" -i "${CMD[@]}" "$f"
done < <(git ls-files -- "$@")