Regular Expressions Tutorial

[Joannelr]

I am looking for a complete tutorial on regular expressions in splunk. A tutorial that will be able to teach from the very start of using regular expressions and searching with them.

Please help and let me know where i can find a tutorial like this? I am using a MacBook Air laptop.

Thank you in advance

[pal_sumit1]

Hi ,
First go through this link ; https://regexone.com/
It will give you basic understanding about what variables we can use while writing regex.

When you finished the above tutorial then go through below link :
https://www.regular-expressions.info/nonprint.html

They have explained everything in detailed manner.

After that just practice as much as you can by taking sample events in below link:
https://regex101.com/

[gururaja0]

Hi

I wnts to extract the particular string from the filed."oozie:action:T=abcd:A=insert:ID=1234-567-oozie-oozi-W\" from this field I wants to extract the values after ID= means "1234-567-oozie-oozi-W\".,Hi
i want to split the number value from below string

oozie:action:T=abc:A=insert:ID=123-45678:oozie:ooz-W. Iwants to extract the value 123-45678:oozie:ooz-W.can some one help me .

Thanks
Raj

[wpreston]

I started off with regex and Splunk by watching some of Michael Wilde's videos over at http://splunkninja.ning.com/

I couldn't download any of the programs either, so I used an online regex tool that let me paste in my own sample data to search against: https://regex101.com/ and used http://www.regular-expressions.info/ for reference.

It really was a bunch of experimentation after that. I had quite a few scenarios where I needed regular expressions and working through them helped me learn. Good luck!

[aljohnson_splun]

RegexOne - Learn Regular Expression with simple, interactive examples !

[jeffland]

Indeed a good place to start.

[raj_mpl]

Good Place to start with regex

[rsennett_splunk]

Actually, this is a very good tutorial (introduction) to regex in the context of Splunk:

http://blogs.splunk.com/2008/10/22/all-my-regexs-live-in-texas/

[MichaelPriest]

Another great site is http://www.regular-expressions.info/

[Joannelr]

I've had a look at that site a few times, however, I cannot download the programs mentioned there as they run on Windows and I'm using Apple...

[jeffland]

For regular expressions, you don't need a tutorial - you need to do it. But to help you do it, there is regex101.com with syntax highlighting, explanations for every part of your expression, and a quick reference for available expressions.

In my experience, regex is strictly learning by doing.

[andrewdore]

I agree with aljohnson. there should at least be a guide for what certain things do so you can learn to use them together.

[niketn]

@andrewdore, do read @jeffland's comment as well. regex101.com site towards bottom right has QUICK REFERENCE with common regex expressions and their meaning.

There are few FLAVORS of Regular Expressions. 99% of case Splunk uses PCRE() Regular Expression type which is on Top Left (selected by default).

Once you have your TEST STRING (sample data) for Regex pattern matching and start typing out your Regular Expression EXPLANATION and MATCH INFORMATION section on right provide you with the plain English explanation of what regular expression is doing and what pattern has matched.

In the Regular Expression Text field there is also Regex Flag selection which gives you information on what they do. Few of them like m and s are important in Splunk based on use case.

While regex101.com is simple crisp repository of everything you might need for Regular Expression in one page, do check out Splunk .conf session on Beyond Regular Regular Expressions by @cpetterborg 's (he's at BOSS level for Regular Expressions :)) http://conf.splunk.com/sessions/2017-sessions.html#search=Beyond%20REGULAR%20Regular%20Expressions&

[joshualemoine]

Thatnks for the .conf session suggestion. Update for anyone who still wants to see it. The link is now @ https://conf.splunk.com/files/2017/recordings/beyond-regular-regular-expressions-v2-point-0.mp4

[aljohnson_splun]

I disagree - they're asking for something pretty specific: "A tutorial that will be able to teach from the very start of using regular expressions and searching with them." I think I understand your point (and partially agree), but its sort of like someone saying they want to learn how to shell script and you just tell them to man everything and have fun. I also really hope someone tell me that is how they learned haha.

[jeffland]

Ok, maybe saying it is "strictly" learning by doing is a bit harsh. I should've explained that after you've grasped the general concept of regular expressions, it is most helpful to have a look at some existing regular expressions with regex101.com (or any other site of that kind) - of course starting from blank there is hard.

[yannK]

this one is also quite complete
http://www.zytrax.com/tech/web/regex.htm

[gyslainlatsa]

hi,
try to read this tutorial:

http://docs.splunk.com/Documentation/Splunk/6.2.3/Knowledge/AboutSplunkregularexpressions