$re = '`\s*(input|output|inout)\s+(wire\s*|reg\s*)?\s*(\[(\d+):(\d+)\])?\s*(\w+)?`';
$str = 'x
input z
input [1:0] az
input wire [1:0] za
input wire [1:0]
y
z
output [12:0] a
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php