I asked for recommendations for Regex editors on stackoverflow a while ago. Following is one of the replies:

What is "good" depends on what is most useful to you. For me, though, these are the key features for a good regex editor (besides the ability to test and create regular expressions, of course, which is a prerequisite to be called a "regex editor" :-) :

  1. Displays matches hierarchically with captured groups.
  2. Explains/analyzes an entered regex in plain English, showing a hierarchical tree.
  3. Translates your regex into code for a language of your choice.

RegexBuddy, as @Max mentioned, does all these but there is also a free alternative, Expresso that also does them very well. These two utilities are the only ones I have found with the crucial ability to explain a regex.

The features sound very attractive to me. But later I found the two are for Windows. I tried to install Expresso, the free one, via Wine, but met some trouble, about which I asked in another post.

  1. So I was wondering if in Ubuntu there are some applications comparable to RegexBuddy and Expresso?
  2. If it is required to install .NET Framework in order to install Expresso, is it still worth to install Expresso on Ubuntu?

Thanks and regards!

8 Answers 8


By far, the best tool for the job is RegExr.

The link above will take you to the online version, which is awesome and definitely the best RegEx tool I've ever used.

If you're looking for something you can install in Ubuntu, then try the desktop version, which is an Adobe Air application:

enter image description here

  • Just to support this answer, i plugged in a crazy complex regex pattern in, along with a load of dummy text and it was able to correctly validate and use the regex (it also found everything it was supposed to match and outlined that match).
    – Thomas Ward
    Mar 21, 2011 at 1:00
  • Thanks! (1) Does Regex desktop version require connection to the Internet? (2) What types of Regex does it support, basic one, Python, Perl, awk, sed, ...?
    – Tim
    Mar 21, 2011 at 2:41
  • @Tim: (1) No. (2) I think it uses AS3's internal RegEx library. That being said, I've found that it is pretty close to PCRE. Mar 21, 2011 at 2:47
  • The link in your answer to the desktop version redirects to regexr.com. Instructions to install RegExr are located on github.com/gskinner/regexr. Aug 6, 2014 at 10:02

Kodos is an application to aid in the creation and debugging of regular expressions in python. The GUI for Kodos should eliminate the need for using the python interpreter for regex design in most instances.

Homepage: http://kodos.sourceforge.net/

Or online tool: http://www.regextester.com/

  • I dont think we're looking for Windows programs, @Wojciech.
    – Thomas Ward
    Mar 21, 2011 at 2:04
  • @EvilPhoneix: Is Kodos Windows or Ubuntu program? I heard it can be used on ubuntu.
    – Tim
    Mar 21, 2011 at 2:43
  • it has an .rpm which can be converted into .deb using alien.
    – Lincity
    Mar 22, 2011 at 14:38
  • I installed Kodos in previous Ubuntu versions trough aptitude, but it seems to be dropped from 12.10. If I download the source and use setup.py I get some dependency errors about pyqt and the manual install bails too. Any chance that there is are working deb somewhere?
    – Brutus
    Nov 29, 2012 at 16:10

visual-regexp still works, and is in the Ubuntu repository. Unfortunately, the name does not start with "regex", so later on you will think, "Oh yeah, what was that regex editor I installed, type "reg", get nothing, go doing a websearch, and ending up here all over again. Also, (because it's Tk-based?), pasting from your paste buffer into the pattern window doesn't seem to work as expected.

Kodos was a wonderful tool, but unfortunately, neither RegExr nor Kodos runs (without great effort) on Ubuntu 12.10+; Kodos has not been upgraded to QT4, and Adobe Air no longer supports Linux.


I've found refiddle.com: it has most features that you would need from a regex editor, and as a bonus you can share your regex with others, or bookmark them.

ex: http://refiddle.com/refiddles/red-green-corpus-test

It's a web application similar to RegExr, built without flash and you can switch between JavaScript, .net and ruby regex processors. Also the corpus-test feature (that I just discovered while posting this) is not bad.


kiki https://launchpad.net/ubuntu/bionic/+package/kiki

fine GUI and awesome features.


I like the website rubular.com its free and you don't have to install anything to use it.

enter image description here

It uses Ruby as underlying framework for regex testing.


(cross post on Software for visually building regular expressions? #167715 - Unix & Linux Stack Exchange)

Here's my attempt at a visual regex GUI tool, called visRegexTester.py:

It has a "live preview" ("Auto rerun") if you type and change the "regex" field. Otherwise it's just that single file; there is a README comment at start - here's a snippet from it:

visRegexTester is a small Python/Tkinter GUI application to assist with writing of regular expressions; tested with Python 2.7 and 3.2. In fact, it is merely an interface for other command line programs: it exploits the fact that a lot of Unix/GNU/Linux programs used as regex processors in the terminal (e.g. grep, sed, perl), have a similar command-line syntax in three parts:


... see the rest of it for more. The screenshot:



https://regex101.com/ is an online (web based) real time regex analyser debugger with cool and helpful features.

Free PCRE-based regular expression debugger with real time explanation, error detection and highlighting.

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