This regular expression matches are two numeric digits from till 99 excluding 00. Match starts from 01 to 99.

find sizes different from standard

*Optional Country code (+xxx|00xxx) *Zone code with optional parenthesis for leading zero. 2-5 digit zone code, with different spacing. *Optional hyphen (optional spaces before and|or after) *Max service number 7 digits. different groups with optional spaces, 2-5 digits per group

Verifies whether two binary numbers a and b are equal to their sum c; Input expected in form a + b = c

Done while modifying Remote MX Wizard( Getting MX records from user input)

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/

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