commandline session
$echo $SHELL /bin/bash $ksh $echo $SHELL /bin/bash $echo $shell $csh % echo $SHELL /bin/bash % exit % exit $exit $ksh $ps PID TTY TIME CMD 3523 pts/1 00:00:00 bash 3573 pts/1 00:00:00 ksh 3574 pts/1 00:00:00 ps $csh % ps PID TTY TIME CMD 3523 pts/1 00:00:00 bash 3573 pts/1 00:00:00 ksh 3575 pts/1 00:00:00 csh 3576 pts/1 00:00:00 ps % exit % exit $ps PID TTY TIME CMD 3523 pts/1 00:00:00 bash 3573 pts/1 00:00:00 ksh 3577 pts/1 00:00:00 ps $exit $ps PID TTY TIME CMD 3523 pts/1 00:00:00 bash 3578 pts/1 00:00:00 ps $