In order to change shell for a particular user of Unix/Linux system without editing /etc/passwd file manually just use command:
chsh -s /path/to/shell username
for example, to change shell to ’sh’ from ‘bash’ for user ‘viper’, use command:
chsh -s /bin/sh viper









Hi,
One can also sudo vim /etc/passwd
and change the shell column from sh to bash
or anything else and then :wq