Find out current shell

To find all of the available shells in your system,

echo $SHELL

/bin/bash

To find out your current shell,

which bash


/bin/bash

ps $$

PID TTY      STAT   TIME COMMAND
29893 pts/0    Ss     0:00 -bash

ps -p $$

PID TTY          TIME CMD
29893 pts/0    00:00:00 bash

Valid login shells

cat /etc/shells

/bin/sh
/bin/bash
/sbin/nologin
/bin/tcsh
/bin/csh
/bin/ksh