#! /usr/local/bin/php
<?php

// Path to my screenshots
$path = '/home/joe/scrots/';

// Path to where the programs on freebsd are
$binpath = '/usr/local/bin/';

// Get a list of all files named *.jpg in that folder
$existing = glob($path.'*.jpg'); 

// We want to increment the name of the file, eg, 
// freebsd1.jpg and then freebsd2.jpg and so on
// Start at one if there are no existing images
$n = 1;

// Go through each file in that list
foreach ($existing as $fp) {

	// Does it match the "freebsdN.jpg" format we want? 
	if (preg_match('/^freebsd(\d+)\.jpg$/', basename($fp), $m))

		// It does; see if the number within is higher than our $n
		// If it is higher, make $n it
		$n = $m[1] > $n ? $m[1] : $n;
}

// At this point $n should be the highest image in the list
// Make it one higher
$n++;

// Name of our file, with absolute path and all
// eg: /home/joe/scrots/freebsd9.jpg
$file = $path.'freebsd'.$n.'.jpg';

// The scrot command saves the screenshot to the filename 
`{$binpath}scrot $file`;

// This command brings up a GUI notification message with the filename as the message
`{$binpath}xmessage $file`;

// Echo out the absolute path so a script can read it as the result of this script
echo $file;