chpasswd - update passwords in batch mode
The chpasswd command reads a list of user name and password pairs from
standard input and uses this information to update a group of existing
users. Each line is of the format:
The supplied passwords must be in clear-text.
PAM is used to update the password in the system database according to
the PAM chpasswd configuration.
When chpasswd fails to update a password, it continues updating the
passwords of the next users, and will return an error code on exit.
This command is intended to be used in a large system environment where
many accounts are created at a single time.
The options which apply to the chpasswd command are:
Report encrypted passwords to stdout instead of updating password
Display help message and exit.
Remember to set permissions or umask to prevent readability of
unencrypted files by other users.
PAM configuration for chpasswd.
passwd(1), newusers(8), useradd(8).