bash $? ssh

ssh $host  "/bin/bash -c 'grep bash2 /etc/shells;echo \$?'" 
                                                                                     ^^^

В дополнение к bigbit:

ssh $host "sh -c 'grep ggggbash /etc/shells'"; echo $?

из man ssh:
"Bash’s exit status is the exit status of the last command executed in the script. If no commands are executed, the exit status is 0."

ааа..
точно... спасибо.