$re = '/( # start of capture group 1
% # literal "%"
(?: # first option
(?:[-+0 #]{0,5}) # optional flags
(?:\d+|\*)? # width
(?:\.(?:\d+|\*))? # precision
(?:h|l|ll|w|I|I32|I64)? # size
[cCdiouxXeEfgGaAnpsSZ] # type
) | # OR
%%) # literal "%%"/x';
$str = 'Worker name is %s and id is %d
That is %i%%
%c
Decimal: %d Justified: %.6d
%10c%5hc%5C%5lc
The temp is %.*f
%ss%lii
%*.*s | %.3d | %lC | %s%%%02d
';
preg_match_all($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