Passwd (command)

Passwd (command)

passwd is a tool on most Unix and Unix-like operating systems used to change a user's password. The passwd entered by the user is run through a key derivation function to create a hashed version of the new password, which is saved. Only the hashed version is stored; the entered password is not saved for security reasons.

When the user logs on, the password entered by the user during the log on process is run through the same key derivation function and the resulting hashed version is compared with the saved version. If the hashes are identical, the entered password must be identical, and so the user is authenticated.

The passwd command may be used to change passwords for local accounts, and on most systems, can also be used to change passwords managed in a distributed authentication mechanism such as NIS, Kerberos, or LDAP.

In the past, it was necessary to have different commands to change passwords in different authentication schemes. For example, the command to change a NIS password was "yppasswd". This required users to be aware of the different methods to change passwords for different systems, and also resulted in wasteful duplication of code in the various programs that performed the same functions with different back ends. In most implementations, there is now a single passwd command, and the control of where the password is actually changed is handled transparently to the user via pluggable authentication modules (PAMs).

See also

* passwd (file)
* passwd (database)

External links

*

ru:/etc/passwd


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Passwd — may refer to:* passwd (command), tool used for changing passwords on Unix and Unix like operating systems. * passwd (database), the source of user information on Unix and Unix like operating systems. * passwd (file), one way to store user… …   Wikipedia

  • Passwd (database) — passwd is a name service database used to store user account information on Unix like operating systems.The sources for the passwd database (and hence the sources of user accounts on a system) are configured, like other name service databases, in …   Wikipedia

  • passwd (Unix) — passwd est une commande UNIX permettant de modifier le mot de passe d un utilisateur. Exemple # passwd autre compte Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully Voir aussi Mot de passe …   Wikipédia en Français

  • passwd (утилита) — У этого термина существуют и другие значения, см. passwd. passwd  утилита Unix систем для управления паролями учётных записей.[1] Использование: passwd [опциональные параметры] После ввода команды последует запрос на ввод существующего… …   Википедия

  • cd (command) — cd, sometimes also available as chdir (change directory), is a command line command to change the current working directory in operating systems such as Unix, DOS, OS/2, AmigaOS (where if a bare path is given, cd is implied), Windows, and Linux.… …   Wikipedia

  • more (command) — more Example output of the more command Developer(s) Daniel Halbert Operating system Cross platform …   Wikipedia

  • Whoami (command) — whoami whoami (Who am I signifiant qui je suis ) est une commande UNIX permettant d afficher le nom de l usager associé à l identificateur effectif (user ID ou UID) courant de l usager. Commandes Unix Aide arch · apropos · cal ·… …   Wikipédia en Français

  • Smbldap-Tools — is a set of scripts designed to help integrate Samba and an LDAP directory. They target both users and administrators of Linux systems although they also work on most Unix systems such as Solaris or AIX. Users can change their password in a way… …   Wikipedia

  • Telnet — (Telecommunication network) is a network protocol used on the Internet or local area network (LAN) connections. It was developed in 1969 beginning with RFC 15 and standardized as IETF STD 8, one of the first Internet standards.The term telnet… …   Wikipedia

  • NetInfo Manager — Developer(s) Apple Computer Stable release 1.4 Operating system …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”