#!/bin/sh -
#
#   Oliver Fromme  <olli@fromme.com>
#
#   BSD-style copyright and standard disclaimer applies.
#
#   Rename one or multiple files, with regular expressions.
#   Example:
#
#   ren foo bar		#  renames xxxfooyyy to xxxbaryyy
#

if [ $# -lt 2 ]; then
	cat <<-EOT >&2
		Usage:  `basename $0` <old> <new> [<file(s)>]
		   <file(s)> is any number of filenames (default: *).
		   <old> is the old substring which is substituted by <new>.
		   sed(1) regular expressions are allowed.
	EOT
	exit 1
fi

RENOLD="$1"
RENNEW="$2"
shift 2
if [ $# -lt 1 ]; then
	set -- *
fi
for FILEOLD in "$@"; do
	FILENEW=`echo "x$FILEOLD" | sed 's/^x//;s/'"$RENOLD"'/'"$RENNEW"'/g'`
	if [ "x$FILEOLD" != "x$FILENEW" ]; then
		mv -- "$FILEOLD" "$FILENEW"
	fi
done

#--