https://wiki.zeropage.org/wiki.php/Linux/RegularExpression

https://regexone.com/
https://regexr.com/ RegExr is an online tool to learn, build, & test Regular Expressions
https://regexcrossword.com/
https://alf.nu/RegexGolf

https://blog.robertelder.org/regular-expression-visualizer/

Links with 설명
A curated collection of awesome Regex libraries, tools, frameworks and software.
https://github.com/aloisdg/awesome-regex

(via hn irrational)
My favorite is https://regex101.com/
But I've found all of the following to be useful:
http://regexone.com/
http://www.regexpal.com/
http://www.rexegg.com/
http://regexr.com/
https://www.debuggex.com/
https://regexper.com/
https://www.regular-expressions.info/
http://www.cheatography.com/davechild/cheat-sheets/regular-expressions/
http://eloquentjavascript.net/09_regexp.html
https://www.smashingmagazine.com/2009/06/essential-guide-to-regular-expressions-tools-tutorials-and-resources/
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
http://codylindley.com/techpro/2013_05_14__javascript-regular-expression-/

매우 느린 정규식을 통한 DoS가 가능. (ReDoS) performance/resource에 대한 공격?
ReDoS: Regular Expression Denial of Service (gitconnected.com)
https://levelup.gitconnected.com/the-regular-expression-denial-of-service-redos-cheat-sheet-a78d0ed7d865
https://news.ycombinator.com/item?id=23676946
정규 표현식 서비스 거부 공격

MKLINK
문자열,string
텍스트,text - plain_text, raw_text, text_file etc
텍스트처리,text_processing
pattern_matching

(DEL OK)
string_search or
string_search_algorithm or
string_algorithm .... string search algorithm string search algorithm

정규 표현식
정규_표현식
Regular_expression