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PASSWD(5)			 File formats			     PASSWD(5)

NAME
       passwd -	password file

DESCRIPTION
       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 user names), 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	*'s  instead  of  encrypted passwords, and the
       encrypted passwords are in /etc/shadow which is readable	by  the	 supe-
       ruser only.

       Regardless  of  whether shadow passwords	are used, many sysadmins use a
       star 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 a star in the password field, then
       use passwd(1) to	set it.

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

	      account:password:UID:GID:GECOS:directory:shell

       The field descriptions are:

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

	      password	the encrypted user password or a star.

	      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 user name.
			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).

NOTE
       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 a star, 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(1),	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).

FILES
       /etc/passwd

SEE ALSO
       passwd(1), login(1), su(1), group(5), shadow(5)

				  1998-01-05			     PASSWD(5)

NAME | DESCRIPTION | NOTE | FILES | SEE ALSO

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