#!/bin/bash
#
# *** USE AT YOUR OWN RISK! ***
#
# License: http://creativecommons.org/licenses/by/3.0/us/
usage()
{
echo "Usage: ${0##*/}
	-u uid		do not alter users below this uid
	-g gid		do not alter groups below this gid
	-p path		start at this path
" 2>&1
exit $1
}
startingUid=""
startingGid=""
startingPath=""
while getopts "u:g:p:" opt
do
	case "$opt" in
		u)	startingUid="$OPTARG";;
		g)	startingGid="$OPTARG";;
		p)	startingPath="$OPTARG";;
		[?])	usage 1;;
	esac
done
if [[ -z "$startingUid" ]] || [[ -z "$startingGid" ]] || [[ -z "$startingPath" ]]
then
	usage 1
fi
echo '#!/bin/bash'
echo '[[ "$USER" != "root" ]] && ( echo "must be root"; exit 1 )'
# fix users
awk -F: '{print $1, $3, $6}' /etc/passwd | \
while read user uid home
do 
	if [[ $uid -ge $startingUid ]]
	then
		echo "[[ -d \"$home\" ]] && chown $user $home"
		echo "find $startingPath -nouser -uid $uid -exec chown $user {} \;"
	fi
done
# fix groups
awk -F: '{print $1, $3}' /etc/group | \
while read group gid
do 
	if [[ $gid -ge $startingGid ]]
	then
		echo "find $startingPath -nogroup -gid $gid -exec chgrp $group {} \;"
	fi
done