passwd man page on Scientific

Man page or keyword search:  
man Server   26626 pages
apropos Keyword Search (all sections)
Output format
Scientific logo
[printable version]

PASSWD(5)		   Linux Programmer's Manual		     PASSWD(5)

       passwd - password file

       Passwd  is  a text file, that contains a list of the system's accounts,
       giving for each account some useful information like user ID, group ID,
       home  directory,	 shell,	 etc.	Often,	it also contains the encrypted
       passwords for each account.  It should  have  general  read  permission
       (many  utilities,  like ls(1) use it to map user IDs to usernames), but
       write access only for the superuser.

       In the good old days there was no great problem with this general  read
       permission.   Everybody	could  read  the  encrypted passwords, but the
       hardware was too slow to crack a well-chosen  password,	and  moreover,
       the  basic  assumption  used  to	 be that of a friendly user-community.
       These days many people run some version of the shadow  password	suite,
       where  /etc/passwd  has	"x"  instead  of  encrypted passwords, and the
       encrypted passwords are in /etc/shadow which is readable by  the	 supe‐
       ruser only.

       If the encrypted password, whether in /etc/passwd or in /etc/shadow, is
       an empty string, login is allowed without even asking for  a  password.
       Note  that this functionality may be intentionally disabled in applica‐
       tions, or configurable (for example  using  the	"nullok"  or  "nonull"
       arguments to

       If  the	encrypted  password  in	 /etc/passwd  is  "*NP*"  (without the
       quotes), the shadow record should be obtained from a NIS+ server.

       Regardless of whether shadow passwords are used, many sysadmins use  an
       asterisk	 in  the  encrypted password field to make sure that this user
       can not authenticate him- or herself using a password.	(But  see  the
       Notes below.)

       If you create a new login, first put an asterisk in the password field,
       then use passwd(1) to set it.

       There is one entry per line, and each line has the format:


       The field descriptions are:

	      account	the name of the user on the  system.   It  should  not
			contain capital letters.

	      password	the  encrypted	user password, an asterisk (*), or the
			letter 'x'.  (See  pwconv(8)  for  an  explanation  of

	      UID	the numerical user ID.

	      GID	the numerical primary group ID for this user.

	      GECOS	This field is optional and only used for informational
			purposes.  Usually, it	contains  the  full  username.
			GECOS  means  General Electric Comprehensive Operating
			System, which has been renamed to GCOS when GE's large
			systems	  division  was	 sold  to  Honeywell.	Dennis
			Ritchie has reported: "Sometimes we sent printer  out‐
			put or batch jobs to the GCOS machine.	The gcos field
			in the password file was a place to stash the informa‐
			tion for the $IDENTcard.  Not elegant."

	      directory the user's $HOME directory.

	      shell	the  program  to run at login (if empty, use /bin/sh).
			If set to a non-existing executable, the user will  be
			unable to login through login(1).


       If  you	want to create user groups, their GIDs must be equal and there
       must be an entry in /etc/group, or no group will exist.

       If the encrypted password is set to  an	asterisk,  the	user  will  be
       unable  to  login  using login(1), but may still login using rlogin(1),
       run existing processes and initiate new ones through  rsh(1),  cron(8),
       at(1),  or  mail	 filters,  etc.	  Trying  to lock an account by simply
       changing the shell field yields the same result and additionally allows
       the use of su(1).

       login(1),   passwd(1),	su(1),	 getpwent(3),  getpwnam(3),  group(5),

       This page is part of release 3.22 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at

Linux				  1998-01-05			     PASSWD(5)

List of man pages available for Scientific

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net