Which THREE of the following are capabilities of the rex command?
The primary use of rex.
Why this answer
The `rex` command can extract fields using regex named groups, where the group name becomes the field name and the matched value becomes the field value. This is a core capability of `rex` for field extraction in Splunk.
Exam trap
Splunk often tests the distinction between `rex` and `sed` commands, where candidates confuse `rex`'s regex extraction with `sed`'s text replacement, or assume `rex` can set default values like `eval` does.