I am a new user of macOS Unix running on MacBook Pro and Mac mini server. I need to change the password for root user account on macOS. How do I change the root password on macOS Unix using command line options?

Introduction – You need to use the passwd command. It is used to update the user’s authentication token(s) i.e. password. Let us see how to change the root user password on macOS Unix.

How to change root password on macOS Unix

The procedure for changing the password of root is as follows:

1. First, log in to the macOS Unix server using ssh or console or terminal app
2. Open a shell prompt/terminal app and type the passwd command to change root password in macOS Unix
3. The actual command to change the password for root on macOS Unix is sudo passwd root

NOTE: Please note that mbp:~ vivek$ is my shell prompt. You need to type commands after the $ prompt.

macOS Unix change root password command

I am going to log in to my macOS based mac mini server using the ssh command:
ssh vivek@macmini-server
If you are using a macbook/MBP, just open the terminal app. Once logged in enter the command passwd as follows:
mbp:~ vivek$ sudo passwd root
First you need to type the password for vivek user. After that the passwd command asks for the new password, which you will have to enter two times:

The next time you log in to a macOS Unix server/workstation, use the new password for root user.

Slightly different procedure for changing passwords in macOS Unix terminal

One can use the following procedure too:
mbp:~ vivek$ ssh user@your-mbp-macmini
Become a root user via the su command or sudo command:
your-mbp-macmini:~ vivek$ sudo -i
Finally change your root user password:
passwd

More on passwd command

The passwd command changes the user’s password. For example, change your own password using the Terminal app, run:
passwd
To change password for user named jerry, run:
sudo passwd jerry

Conclusion

This page explained the process for changing the password of root user using the passwd command on a macOS Unix system. For more information see the passwd command man page by typing the following man command:
man 1 passwd
man 5 passwd