Splunk® Cloud Services

SPL2 Search Manual

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Using comments in SPL2

You can add comments to your search string to explain a portion of a search, or to use as a troubleshooting technique. SPL2 supports both block comments and line comments.

  • Block comments use this tagging: /* ... */
  • Line comments use this tagging: //

Block comments

Block comments begin with a leading forward slash followed by an asterisk and end with a trailing asterisk and forward slash.

For example, suppose you have the following search:

... | eval bytes = k * 1024 | stats sum(bytes) by host

You want to add a comment that explains what the k field contains.

... | eval bytes = k * 1024 /* k contains kbytes */ | stats sum(bytes) BY host


Here's another example.

The following search classifies recent earthquakes based on their depth:

| FROM index=mydataset WHERE source=usgs | eval Description=case(depth<=70, "Shallow", depth>70 AND depth<=300, "Mid", depth>300, "Deep") | stats count(), min(mag), max(mag) BY Description

When you add comments to a search, the search is easier to understand. This is the same search with multiple block comments added to explain each part of the search:

| FROM index=mydataset WHERE source=usgs /* The source is the us geological service (usgs) */ | eval Description=case(depth<=70, "Shallow", depth>70 AND depth<=300, "Mid", depth>300, "Deep") /* Creates the field Description. Case function specifies earthquake depths. Returns Description values - Shallow, Mid, Deep. */ | stats count(), min(mag), max(mag) /* Counts earthquakes. Displays min and max magnitudes */ BY Description

Alternatively, you can use block comments at the start or end of a search string. For example:

/* The source is the US geological service (USGS). Eval creates the field Description. Case function specifies the earthquake depths. Returns Description values - Shallow, Mid, Deep. Stats counts earthquakes. Displays min and max magnitudes */ | FROM index=mydataset WHERE source=usgs | eval Description=case(depth<=70, "Shallow", depth>70 AND depth<=300, "Mid", depth>300, "Deep") | stats count(), min(mag), max(mag) BY Description


You cannot have block comments in any portion of your search that uses the search command.

Line comments

You can use line comments within any command in your search pipeline. Line comments begin with a double forward slash ( // ) and end with a new line.

For example:

... | eval bytes = k * 1024 // the k field contains kilobytes | stats sum(bytes) by host

Using comments to troubleshoot a search

The following search example is attempting to return a sum of the bytes for a specific range of IP addresses, organized by host names. However, the search has a misspelling for field name in the stats command BY clause.

| FROM main WHERE ipaddress LIKE "198.%" | stats sum(bytes) BY hosts

You can comment out portions of your search to help identify problems. In this search, the stat portion of the search is commented out:

| FROM main WHERE ipaddress LIKE "198.%" // | stats sum(bytes) BY hosts

The results show that the correct name to use for the field is host and not hosts.

The following search shows the correct syntax:

| FROM main WHERE ipaddress LIKE "198.%" | stats sum(bytes) BY host

Last modified on 23 June, 2021
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This documentation applies to the following versions of Splunk® Cloud Services: current


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