1. Edit /etc/passwd and find the user whose shell you want to change and replace
/bin/sh to /bin/bash
2. Login as root and fire the command chsh -s /bin/bash {username}
Now log out and login as the username
The newbash should appear.
/bin/sh to /bin/bash
2. Login as root and fire the command chsh -s /bin/bash {username}
Now log out and login as the username
The newbash should appear.