#!/bin/bash
#
# parallel-script-demo.sh v0.1.1
# Copyright 2010, Nikita Melnichenko [http://nikita.melnichenko.name]
# License: GPL-2 (http://opensource.org/licenses/gpl-license.php)
#
# Parallel processing script demo.

# process a single item
function process_item
{
	local n
	let n="$RANDOM%5+1"
	echo "> $1 ($n sec)"
	sleep $n
	echo "< $1"
}

# generate and process the list of items
function process_list
{
	dir="$2"
	if [ -z "$dir" ]; then dir=/; fi
	find "$dir" -mindepth 1 -maxdepth 1 -print0 | sort -z | xargs -0 -l1 -P"$1" "$0" 0
}

# handle the first argument of the script
function process
{
	default_np=4
	np="$1"; shift
	if [ -z "$np" ]; then np=$default_np; fi
	if [ "$np" == "0" ]; then process_item "$@"; else process_list "$np" "$@"; fi
}

process "$@"