To find the current shell instance, look for the process (shell) having the PID of the current shell instance. Show activity on this post. $SHELL gives you the default shell. $0 gives you the current shell.

How do I know my shell version Ubuntu?

Open your terminal either by using the Ctrl+Alt+T keyboard shortcut or by clicking on the terminal icon. Use the lsb_release -a command to display the Ubuntu version. Your Ubuntu version will be shown in the Description line.

How do I know bash or shell?

To test the above, say bash is the default shell, try echo $SHELL , and then in the same terminal, get into some other shell (KornShell (ksh) for example) and try $SHELL . You will see the result as bash in both cases. To get the name of the current shell, Use cat /proc/$$/cmdline .