The chpasswd command is used to change passwords, although the passwd command can also perform the same operation. But it changes the password of one user at a time, so for multiple users, use chpasswd. The following figure shows the use of passwd command. Using passwd we are changing the guest user's password. First, you must enter the password of the current signing user, and then change the password of any other users. Requires administrator rights.
The chpasswd command reads multiple colon-separated usernames and passwords using standard input or a file and then encrypts them based on options.