# chsh --list
/bin/sh
/bin/bash
/sbin/nologin
/bin/tcsh
/bin/csh
/bin/ksh
		

neo@netkiller:~$ chsh -s /bin/zsh
or
$ usermod -s /bin/zsh
		

show me current shell

neo@netkiller:~$ echo $SHELL
/bin/zsh

neo@netkiller:~$ cat /etc/passwd|grep neo
neo:x:1000:1000:Neo Chen,,,:/home/neo:/bin/zsh