#!/bin/sh -
#
#   Oliver Fromme  <olli@fromme.com>
#
#   BSD-style copyright and standard disclaimer applies.
#

usage()
{
	echo "Usage:  `basename $0` <start> <format> <files ...>" >&2
	echo "<start>  is the first number." >&2
	echo "<format> should contain a single printf-style % sequence" >&2
	echo "         which is used to format the numbers." >&2
	exit 1
}

if [ $# -lt 3 -o `expr "x$1" : "x-"` -gt 0 ]; then
	usage
fi

case "$1" in
	""|*[!0-9]*)
		usage
		;;
esac

case "$2" in
	*%?*)
		;;
	*)
		usage
		;;
esac

case `uname -s` in
	FreeBSD|Linux)
		INCREMENT='I=$(( $I + 1 ))'
		;;
	*)
		INCREMENT='I=`expr 1 + "$I"`'
		;;
esac

I="$1"
FMT="$2"
shift 2
for FILE in "$@"; do
	mv "$FILE" "$FILE".renumber.tmp
done
for FILE in "$@"; do
	NEW=`printf "$FMT" "$I"`
	printf '%s\t--> %s\n' "$FILE" "$NEW" >&2
	mv "$FILE".renumber.tmp "$NEW"
	eval "$INCREMENT"
done

#--