Hi,
Is there any way to execute a linux query and fetch the results of it in the Splunk search board?
Following this I have written a condition to send an alert based on the command output.
Yes, it can be done. Use a scripted input to execute the Linux command and the results will be indexed automatically. Have a look at the Splunk Add-on for Unix and Linux (Splunk_TA_nix) at https://splunkbase.splunk.com/app/833 for examples. It collects data the way you describe. Once the data is collected and indexed then you can write an alert for it.