exit

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
$