grep: unknown device method

Today while using grep command via rundeck I was through grep: unknown device method error.

And the reason is due to I am having ' - ' in my search pattern I was through this error.

I mean search includes

grep "-search.this" /path/to/file

Then you may get error with grep. So remove ' - ' in pattern and repeat your search.

grep "search.this" /path/to/file

Hope that helps.