When I execute a command as below it gives me an output as expected but when I run the same command on remote server it always gives me echo $? as 0.
locally
# <some command>
# echo $?
Remotely
# ssh server " <some command >; echo $? "
Now in case of remote execution I always get 0 as echo $? output.
The $? is evaluated before the command is sent to the remote machine. Effectively, you are sending the command echo 0. Try
ssh server ' <some command >; echo $? '
As Michael Hampton points out, single quotes prevent evaluating variables etc. before sending them to the remote command, while double quotes allow that.
