return
Description
Use the return
command to return values from a subsearch. return
replaces the incoming events with one event, with one attribute: "search". To improve performance, the return
command automatically limits the number of incoming results with the head
command and the resulting fields with the fields
command.
By default, the return
command uses only the first row of results. Use the count
argument to specify the number of results to use.
Syntax
return [<count>] [<alias>=<field>...] [<field>...] [$<field>...]
Required arguments
None.
Optional arguments
- <count>
- Syntax: <int>
- Description: Specify the number of rows.
- Default: 1, which is the first row of results passed into the command.
- <alias>
- Syntax: <alias>=<field>...
- Description: Specify the field alias and value to return. You can specify multiple pairs of aliases and values, separated by spaces. The
<alias>
argument does not support spaces before and after the '=' sign.
- <field>
- Syntax: <field>...
- Description: Specify one or more fields to return, separated by spaces.
- <$field>
- Syntax: <$field>
- Description: Specify one or more field values to return, separated by spaces.
Usage
The command is convenient for outputting a field name, a alias-value pair, or just a field value.
Output | Example |
---|---|
Field name | return source
|
Alias=value | return ip=srcip
|
Value | return $srcip
|
By default, the return
command uses only the first row of results. You can specify multiple rows, for example 'return 2 ip
'. Each row is viewed as an OR clause, that is, output might be '(ip=10.1.11.2) OR (ip=10.2.12.3)
'. Multiple values can be specified and are placed within OR clauses. So, 'return 2 user ip
' might output '(user=bob ip=10.1.11.2) OR (user=fred ip=10.2.12.3)
'.
In most cases, using the return
command at the end of a subsearch removes the need for head
, fields
, rename
, format
, and dedup
.
Duplicate values
Suppose you have the following search:
sourcetype=WinEventLog:Security | return 2 user
You might logically expect the command to return the first two distinct users. Instead the command looks at the first two events, based on the ordering from the implied head
command. The return
command returns the users within those two events. The command does not determine if the user value is unique. If the same user is listed in these events, the command returns only the one user.
To return unique values, you need to include the dedup
command in your search. For example:
sourcetype=WinEventLog:Security | dedup user | return 2 user
When the input for 'return' is 0 events
When the input to the return
command is 0 events, the results of the search can be misleading. To avoid this, test your subsearches outside of the main search to verify that they return events.
For example, say you have the following search:
index=B [index=A test_error | return clientip]
If index=A test_errror
returns 0 events, the subsearch returns an empty string. The final result of the full search is all events from index=B
. If you are unaware of the result of the subsearch, this could lead you to believe that all events from index=B
satisfied the condition of having test_error
for their clientip
, when in fact none did.
Quotations in returned fields
The return
command does not escape quotation marks that are in the fields that are returned. You must use an eval
command to escape the quotation marks before you use the return
command. For example:
...[search eval field2=replace(field1,"\"","\\\"") | return field2]
If you encounter problems with the return command
If you encounter difficulties when running the return
command, consider running the oldreturn
command instead. oldreturn
is a deprecated version of return
that does not require spaces around the =
symbol for the alias
argument. The tradeoff is that oldreturn
searches complete slower than return
searches.
Examples
Example 1:
Search for 'error ip=<someip>
', where <someip> is the most recent ip used by user 'boss'.
error [ search user=boss | return ip ]
Example 2:
Search for 'error (user=user1 ip=ip1) OR (user=user2 ip=ip2)
', where the users and IPs come from the two most-recent logins.
error [ search login | return 2 user ip ]
Example 3:
Return to eval the userid of the last user, and increment it by 1.
... | eval nextid = 1 + [ search user=* | return $id ] | ...
See also
rest | reverse |
This documentation applies to the following versions of Splunk Cloud Platform™: 8.2.2112, 8.2.2201, 8.2.2202, 8.2.2203, 9.0.2205, 9.0.2208, 9.0.2209, 9.0.2303, 9.0.2305, 9.1.2308, 9.1.2312, 9.2.2403, 9.2.2406 (latest FedRAMP release)
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