/etc/passwd
System password file to be changed
Change login password
npasswd [-P]
[-V]
[username]
Npasswd changes or installs a login password for username (your own by default). Only the super-user can change another users' password.
When changing a password, npasswd prompts for the old password and then for the new one. The new password must be typed twice to forestall mistakes. The new password is checked for reasonableness.
Npasswd accepts the option switches of the 4.3BSD and SunOS 4.X passwd but impliments none of them. The -V option prints version and patch level information.
The -P option indicates that npasswd will be fed input from another program via a pipe. This option is reserved for the super-user.
Npasswd can change both local passwords and passwords in a Network Information Service (aka Yellow Pages) database.
Npasswd will not accept passwords that:
Are less than 6 characters long.
Match anything in your UNIX account information, such as your login name or an item from your "finger" data entry.
Are found in the system's spelling dictionary.
Have less than 5 different characters.
Are entirely single case letters.
Fail any of these tests when reversed, pluralized, or truncated.
/etc/passwd
System password file to be changed
/etc/passwd~
Backup copy of previous passwd file
/etc/ptmp
Lock file for /etc/passwd
/etc/npasswd/npasswd.conf
Configuration file for npasswd
/etc/npasswd/npasswd.help
Help file for npasswd
/etc/npasswd/npasswd.motd
Message printed when npasswd is run
Various, hopefully self-explanitory.
Unchanged in 2 releases since Debian 1.1 (Buzz).