我可以从ssh命令获得某种返回值吗？

Question

I'm running the following command in a while loop, going through a list of machines:

ssh -n -o ConnectTimeout=10 hostname 'smbios-sys-info' >> MACHINEINFO

Works great. Except when I run into a connection that fails or times out, it outputs the timeout error message into MACHINEINFO. I instead want it to silently fail without muddling MACHINEINFO, but instead write the hostname of the failed connection into another file like FAILEDMACHINES.

I assume to do something like this I'd need to get a return value from ssh to determine whether or not the connection and smbios-sys-info command ran successfully, and if not, output to FAILEDMACHINES.

Answer 1

After running the command, $? will give you the result code.

If the ssh succeeds, $? will be the result code of the remote command, otherwise, it will return 255.