A good enough approximation to IPv6 based on the examples at https://www.ibm.com/docs/en/ts3500-tape-library?topic=functionality-ipv4-ipv6-address-formats

Matches palindromes: arbitrary length ignores non-significant characters (spaces, ponctuation) ignores accents, provided the text is NFD-normalized recursive palindromes (e.g. "a été à"): either match the longest one ("a été à") or the nested ones individually ("a", "été", "à") (see comment)

IDN Domains & Normal Domains This regex is able to identify any type of domain or subdomain whether it is IDN or normal, this includes domains in emojis, non-Latin characters, etc.

POSIX ERE compatible, suitable for usage in Bash [ testing Attributions Derived from [regex101: RFC1918 - Private IPv4 addresses by 0100101101001.

https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file Integer value zero, sometimes referred to as the ASCII NUL character. Characters whose integer representations are in the range from 1 through 31, except for alternate data streams where these characters are allowed. For more info...

Regular expression to check the email syntax validity. Certainly requires improvement, but it's a good basis to work from. Work with Java and JavaScript.

this is some cursed shit, but it does work. I use it to check whether all my ROMs have valid names or not. Makes it easier to read and, more importantly, deduplicate.

Test your RSS pubDate has a correctly formatted date value according to the RFC822 standard It will match timeZoneName (eg GMT, EST) or time zone offset (eg. +0100)

This was build on gentoo with english_ca.utf8 IIRC. Might not work for other distros... or locales supports -as the delimiter of hostname suffixing/prefixing

This is the best regex I found that was able to correctly parse cells containing multiple lines (hard line breaks). Low number of steps with sufficient speed, and it doesn't require /x option either. Source: https://gist.github.com/awwsmm/886ac0ce0cef517ad7092915f708175f

uncode word boundaries

thanks

\tilde \alpha

test

japanese text to bold japanese text 食べるんだ 食べるんだ

improved "Ahmed Z" regexp. PHP date format (and input[type=text] format date too): YYYY-MM-DD. Year between [1900-2099]. No leap year check. Month 02 is limited to 29 days.

youtube id 17 matches

Validates a date with ISO 8601 format. Source: http://www.pelagodesign.com/blog/2009/05/20/iso-8601-date-validation-that-doesnt-suck/

white space before punctuations, outside script and code tags