Modify a user password.
-d, –delete delete the password for the named account (root only)
-f, –force force operation (effectively calls &qt;chfn&qt;&qt;?)
-k, –keep-tokens keep non-expired authentication tokens
-l, –lock lock the named account (root only)
-S, –status report password status on the named account (root only)
–stdin read new tokens from stdin (root only)
-u, –unlock unlock the named account (root only)
-?, –help Show this help message
–usage Display brief usage messageIf no options are specified – passwd will change the password of the currently logged in user – will prompt for the old and new passwords.
Password aging (for new accounts) can be set to enforce a limited lifetime for each password: /etc/login.defs
parameters: PASS_MAX_DAYS, PASS_MIN_DAYS, PASS_WARN_AGE