chsh

• Change default shell
• The shell binary must be authorized in /etc/shells
• The default shell is defined per user and it's stored at /etc/passwd

# Change the default shell for the current user
chsh -s "shell"

# Example for zsh
chsh -s $(which zsh) # Log out to apply!

# Check the user shell
cat /etc/passwd | grep "username"
echo $SHELL