git-subst

#!/usr/bin/env bash

#
# INSTALLATION
#
# ln -s ${PWD}/git-subst $(brew --prefix)/bin/
# sudo ln -s ${PWD}/git-subst /usr/local/bin/
#

FROM="$1" ;
TO="$2" ;

[ -z "${FROM}" ] && { # check command-line options
	>&2 printf 'Replace <from> with <to>:\n' ;
	>&2 printf '  git subst <from> <to> [<file>...]\n' ;
	>&2 printf '\n' ;
	>&2 printf 'Delete <pattern>:\n' ;
	>&2 printf '  git subst <pattern> '"''"' [<file>...]\n' ;
	>&2 printf '\n' ;
	exit 1 ;
}

shift ; # exclude ${FROM} from [<file>...] list
shift ; # exclude ${TO} from [<file>...] list

DELIM=$'\a' ; # use 'BEL' as delimiter in sed addresses and commands

MATCH="\\${DELIM}${FROM}${DELIM}" ;              # /<from>/
SUBST="s${DELIM}${FROM}${DELIM}${TO}${DELIM}g" ; # s/<from>/<to>/g

git grep -l "${FROM}" "$@" | while read -r FILE ; do
	sed -i "" -e "${MATCH}{ ${SUBST}; }" "${FILE}" ;
done

# That's all Folks!