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Regex fails as when defined as field extraction, but works with rex command. "Regex: missing terminating ] for character class"

Communicator

This works in my search:

``````rex field=source "\w:\\\[\w]*\\\(?<app_path>[^\\\]*)"
``````

But when I try to define it as a field extraction I get the following error:

Encountered the following error while
trying to save: In handler
'props-extract': Regex: missing
terminating ] for character class

All the parens are clearly balanced... what is going on here?

Splunk Employee

In the `rex` command, you need an extra level of escaping of the string (much like you need an extra level of escaping of characters when you specify regexes on the bash command line). But when you define a field extraction in props directly, you need to just specify the regex without the outer layer of escaping. So your base regex should be simply:

``````\w:\\[\w]*\\(?<app_path>[^\\]*)
``````

Assuming you're trying to get `my_app` out of something like `c:\base\my_app\whatever\file.txt`

Builder

Most likely reason - escaping slashes.