#!/bin/sh -e
# Rename a file with a backup suffix or revert it
# Add -a to act on multiple files,
# otherwise the second arg is used as suffix rather than the default "bak".
if test "$1" = "-a"; then
	shift
	for arg; do "$0" "$arg"; done
	exit $?
fi
suffix="${2:-bak}"
orig="${1%%.$suffix}"
smv () {
	eval source=\$$(($#-1))
	if test -w "$source"
	then mv -v "$@"
	else sudo mv -v "$@"
	fi
}
if test -e "$orig.$suffix"
then
	test -e "$orig" && smv "$orig" /tmp
	smv -n "$orig.$suffix" "$orig"
else
	smv -n "$1" "$1.$suffix"
fi