I am exec command:
yum info mcrypt | grep -i error > /dev/null yum info mcrypt | grep -i error 2> /dev/null
But i see:
Error: No matching Packages to list
How I can hide this messasge from stdout?
Its not exactly clear what you are trying to do - Why would you "grep" for an error message you don't want.
I suspect the problem you are having may be that you are diverting stderr after it has been displayed - you may want to be using
yum info mcrypt 2>/dev/null | grep -i "error"
Or, if you are simply wanting to ignore the error,
yum info mcryp3t 2>/dev/null