Check shortcode

(am|sg){0,1}(invoice){0,1}(\d*){0,1}

grep logs with X username and Y response code

Regex to make sure directories have a "real" name and not code use for scripting/

Filter authentication fails from /var/log/roundcube/error

It checks the string to be only letters with no spaces or any other char than a-z and A-z

this is trim-like regex

IPv4 Address Input

Parse DocBlock tags to name & value