It is a skill set that’s quick to pick up and master, and learning it can take your Splunk skills to the next level. Using regex can be a powerful tool for extracting specific strings. Use to practice your RegEx: Figure 5 – a practice search entered into We’re Your Regex(pert) Syntax for the command: | rex field=field_to_rex_from “FrontAnchor(? = searches for digits that are 1-3 in length, separated by periods. When using regular expression in Splunk, use the rex command to either extract fields using regular expression-named groups or replace or substitute characters in a field using those expressions. I have sorted them into a table, to show that other CVE_Number fields were extracted: Figure 2 – the job inspector window shows that Splunk has extracted CVE_Number fields The rex Commands Next, by using the erex command, you can see in the job inspector that Splunk has ‘successfully learned regex’ for extracting the CVE numbers. I want to have Splunk learn a new regex for extracting all of the CVE names that populate in this index, like the example CVE number that I have highlighted here: Figure 1 – a CVE index with an example CVE number highlighted In this screenshot, we are in my index of CVEs. Syntax for the command: | erex examples=“exampletext1,exampletext2” When using regular expression in Splunk, use the erex command to extract data from a field when you do not know the regular expression to use. Let’s get started on some of the basics of regex! How to Use Regex The erex command In Splunk, regex also allows you to conduct field extractions on the fly. Regex is a great filtering tool that allows you to conduct advanced pattern matching. A Regular Expression (regex) in Splunk is a way to search through text to find pattern matches in your data. Especially data that’s hard to filter and pair up with patterned data.

How to use splunk