Splunk's Search Processing Language (SPL) utilizes a standard set of comparison operators for filtering events and evaluating expressions, primarily within commands like search, where, and eval. The valid operators include =, !=, >, =, and <=. The symbol ?= is not a recognized or valid comparison operator within the Splunk SPL syntax. Its inclusion in a search query would result in a syntax error.

A. <= is a valid Splunk operator used to test if a value is less than or equal to another value.
B. = is a valid Splunk operator used for equality comparison. It is a synonym for ==.
C. != is a valid Splunk operator used for inequality comparison. It is a synonym for .
D. > is a valid Splunk operator used to test if a value is greater than another value.

1. Splunk Enterprise Documentation

Search Reference

"eval" command.

Section: Usage -> Operators

Content: The documentation explicitly lists the comparison operators that can be used with the eval command. The list includes: ==

!=

<

>

<=

>=. It also notes that = is a synonym for == and is a synonym for !=. The operator ?= is not present in this list.

2. Splunk Enterprise Documentation

Search Reference

"where" command.

Section: Syntax -> Required arguments

Content: The documentation for the where command describes its syntax

which uses comparison expressions. The examples and description confirm the use of standard operators like =

>

<

!=

etc. There is no mention or example of a ?= operator.