A script is defined in the inputs.conf file
[script:///opt/splunkforwarder/bin/scripts/top.sh] interval = 0 0 * * *
How can I check whether the script has indeed run.
Is there a log file to check.
The error messages for scripted input can be found by searching the _internal index. So a search for your script might be:
index=_internal error top.sh
Here is a link to the scripted input documentation: https://docs.splunk.com/Documentation/Splunk/8.0.0/AdvancedDev/ScriptedInputsIntro
