Short-Tail

	#!/usr/bin/env bash
	HELP="Usage: $0 [-n LINES] [-p PREFIX] [-w] [-h]
	Continuously displays the last '-n' lines of 'stdin'.
	Parameters:
	-n Number of lines to display (default: 5).
	-p PREFIX Prefix lines with 'PREFIX'.
	-w Preserve blank lines (default: false).
	-h Display this help
	";
	function real_len() {
	# Measure the length of a string, stripped of control characters.
	local trimmed;
	trimmed=$(echo "$@" | sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{1,2})?)?[mGK]//g")
	echo ${#trimmed};
	}
	# Process options
	while getopts 'hn:p:o:w' name; do
	case "$name" in
	o) out="$OPTARG";
	if ! touch "$out"; then
	echo "Failed to create output file.";
	exit 2;
	fi;;
	p) prefix="$(tput sgr0)$OPTARG";;
	n) lines="$OPTARG";
	[ -n "$lines" ] && [ "$lines" -eq "$lines" ] 2>/dev/null;
	if [ $? -ne 0 ] || [ "$lines" -lt 1 ]; then
	echo "-n LINES must be a number greater than 0";
	exit 2;
	fi;;
	w) whitespace=false;;
	h|*) echo "$HELP";
	exit 2;;
	esac
	done
	# Check for unexpected options
	shift "$((OPTIND - 1))";
	if [ -n "$*" ]; then
	echo "Unexpected options: $*";
	echo "$HELP";
	exit 2;
	fi
	lines="${lines:-5}"
	out="${out:-/dev/null}"
	whitespace="${whitespace:-true}"
	width="$(stty size </dev/tty | cut -d' ' -f2)"
	(( width-=$(real_len "$prefix") ))
	i=0
	while IFS= read -r line; do
	if $whitespace; then
	case "$line" in
	(*[![:blank:]]*);;
	(*) continue;;
	esac
	fi
	if [[ $((++i)) -gt "$lines" ]]; then
	tput cuu "$lines"; tput dl1;
	if [[ "$lines" -gt 1 ]]; then tput cud "$(( lines - 1 ))"; fi;
	fi
	echo -n "$prefix";
	echo "$line" | cut -c1-$width;
	done < <(tee "$out" </dev/stdin)