It validates an email address with alias

with Leap Year support (dd/MM/yyyy)

match with or without prevailing/trailing slashes

get special tag contains html link

Remove multiple white spaces between words and replace it with the char of your choosing.

Extract parts of an URL.

RegEx for an .htaccess rewrite into a subfolder without provoking a 'too many redirects' error

^((?!proposed_).)*((project|task)_details) matches: project_details task_details...

This expression matches human genomic coordinates, similat to those being used by genome browsers (e.g. the UCSC Genome Browser). It can match: chromosome, chromosome start, chromosome start end, chromosome start end reference sequence, chromosome start end reference sequence alternative sequence. T...

Splitting string on parts. Able quoted strings and escaped chars. Without optimizations. command arg1 "string arg \"qoute\" demo" arg3

Regex to match an IPv4 address at beginning