#!/usr/local/bin/perl

# Poor man's "at": execute script or command at a time increment from now

# Usage:

# at [-c] [ -s sec | -m min | -h hours ] scriptname

# -c means script is given on command line (use \>, etc to protect)
#                                          (or enclose all in " " )
#                                          (or enclose each in " ")

$time = 5;	# default wait time

$helpline="14";

if ( $ARGV[0] =~ /-he/ ) {
	system("head -$helpline $0");
	exit 0;
}

chop($name = `basename $0`);

if ( $ARGV[0] ne '-c' ) {	# Script is file
	if ( $ARGV[0] !~ /^-(s|m|h)/ ) {
		$script = $ARGV[0];
	} else {
		$script = $ARGV[2];
	}
	if ( ! -f $script ) {
		print STDOUT "Script $script does not exist";
		exit 1;
	}
} else {			# Script is rest of command line
	shift;
	if ( $ARGV[0] !~ /^-(s|m|h)/ ) {
		$script = join(' ',@ARGV[0 .. $#ARGV]);
	} else {
		$script = join(' ',@ARGV[2 .. $#ARGV]);
	}
	print "$name: script is: $script\n";
}


if ( $ARGV[0] eq '-s' ) {
	$time = $ARGV[1];
} elsif (  $ARGV[0] eq '-m' ) {
	$time = $ARGV[1]*60;
} elsif (  $ARGV[0] eq '-h' ) {
	$time = $ARGV[1]*3600;
}

if ( $time < 0 ) { $time = 10; }	# just in case

if ( $pid = fork ) {			# fork child to sleep then run
	exit 0;
} elsif ( defined $pid ) {
	sleep $time;
	eval system "$script";
	exit 0;
}