#!/bin/sh

_usage () {
	cat<<EOF
Usage: ${1##*/} [OPTIONS] [FILES]

Cut out last 10 lines from stdin. If FILES are provided, cut files instead of
stdin and output to stdout.

Note: GNU 'head' has the '-n -10' option to do this. This program is only useful
for non-GNU systems.

Options:

  -f:    Cut out first 11 instead of the last. Like 'tail -n +11' with GNU tail (11
         because the limit line is included).
  -h:    Show this help.
  -i:    Replace file content instead of writing to stdout.
  -n N:  Cut N lines instead of 10.

EOF
}

OPT_CUTFIRST=false
OPT_LINES=10
OPT_INPLACE=""
while getopts ":fhin:" opt; do
	case $opt in
	f)
		OPT_CUTFIRST=true ;;
	h)
		_usage "$0"
		exit 1 ;;
	i)
		OPT_INPLACE="-i" ;;
	n)
		OPT_LINES=$OPTARG ;;
	\?)
		_usage "$0"
		exit 1 ;;
	esac
done

shift $(($OPTIND - 1))

if $OPT_CUTFIRST; then
	sed $OPT_INPLACE -n "1,${OPT_LINES}!p" "$@"
else
	echo CUTLAST
	sed $OPT_INPLACE -n ":begin ; 1,${OPT_LINES}!{P;N;D}; N; b begin" "$@"
fi