private static function commandExists($command) {
		$whereIsCommand = (PHP_OS == 'WINNT') ? 'where' : 'which';
		$process = proc_open("$whereIsCommand $command", [
			0 => array("pipe", "r"), //STDIN
			1 => array("pipe", "w"), //STDOUT
			2 => array("pipe", "w"), //STDERR
				], $pipes);

		if ($process !== false) {
			$stdout = stream_get_contents($pipes[1]);
			$stderr = stream_get_contents($pipes[2]);
			fclose($pipes[1]);
			fclose($pipes[2]);
			proc_close($process);

			return $stdout != '';
		}

		return false;
	}
private static function commandExists($command) {
		$whereIsCommand = (PHP_OS == 'WINNT') ? 'where' : 'which';
		$process = proc_open("$whereIsCommand $command", [
			0 => array("pipe", "r"), //STDIN
			1 => array("pipe", "w"), //STDOUT
			2 => array("pipe", "w"), //STDERR
				], $pipes);

		if ($process !== false) {
			$stdout = stream_get_contents($pipes[1]);
			$stderr = stream_get_contents($pipes[2]);
			fclose($pipes[1]);
			fclose($pipes[2]);
			proc_close($process);

			return $stdout != '';
		}

		return false;
	}
private static function commandExists ( $ command ) { $ whereIsCommand = ( PHP_OS == 'WINNT' ) ? 'where' : 'which' ; $ process = proc_open ( "$whereIsCommand $command" , [ 0 => array ( "pipe" , "r" ) , //STDIN 1 => array ( "pipe" , "w" ) , //STDOUT 2 => array ( "pipe" , "w" ) , //STDERR ] , $ pipes ) ; if ( $ process !== false ) { $ stdout = stream_get_contents ( $ pipes [ 1 ] ) ; $ stderr = stream_get_contents ( $ pipes [ 2 ] ) ; fclose ( $ pipes [ 1 ] ) ; fclose ( $ pipes [ 2 ] ) ; proc_close ( $ process ) ; return $ stdout != '' ; } return false ; }
Determines if a command exists on the current environment

@link http://stackoverflow.com/a/18540185
@param string $command The command to check
@return bool True if the command has been found ; otherwise, false.
Determines if a command exists on the current environment