/etc/default/passwd

This file contains the following information about the length and aging of user passwords and the availability of the passwd command for changing user passwords:

MINWEEKS

Minimum number of weeks before a password can be changed.

MAXWEEKS

Maximum number of weeks a password can be unchanged.

PASSLENGTH

Minimum number of characters in a password.

WARNWEEKS

Number of weeks before a password expires that the user is to be warned.

LOGIN_ONLY

If this parameter exists and its value is equal to Yes, an unprivileged user can change passwords only by invoking the login(1) command with the -p option. If it does not exist, or its value is anything other than the string Yes (including NULL), an unprivileged user can change passwords using the passwd(1) command.