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passwd(5yp) [ultrix man page]

passwd(5yp)															       passwd(5yp)

       passwd - password file description with the Yellow Pages service implemented

       The  file  stores  initial login information, including passwords for each user in the system.  Regardless of whether or not the system has
       the Yellow Pages service implemented, the file contains the following information:

       Name (login name, contains no uppercase)
       Encrypted password
       Numerical user ID
       Numerical group ID
       User's real name, office, extension, home phone.
       Initial working directory
       Program to use as Shell

       The name can contain an ampersand (&), meaning insert the login name.  This information is set by the command and used by the command.

       This is an ASCII file.  Each field within each user's entry is separated from the next by a colon.  Each user is separated from the next by
       a new line.  If the password field is null, no password is demanded; if the shell field is null, the system defaults to the shell.

       This  file resides in the directory.  Because of the encrypted passwords, it can and does have general read permission and can be used, for
       example, to map numerical user IDs to names.

       Appropriate precautions must be taken to lock the file against simultaneous changes if it is to be edited with a text editor.  The  command
       does the necessary locking.

       In  a Yellow Pages environment, the file can also have a line beginning with a plus (+), which means to incorporate entries from the Yellow
       Pages data base.  There are three styles of + entries: by itself, + means to insert the entire contents of the Yellow Pages  password  file
       at  that  point;  +name means to insert the entry (if any) for name from the Yellow Pages at that point; +@name means to insert the entries
       for all members of the network group name at that point.  If a + entry has a nonnull password, directory, gecos, or shell  field,  it  will
       override what is contained in the Yellow Pages.	The numerical user ID and group ID fields cannot be overridden.

       Here is a sample file:
       root:q.mJzTnu8icF.:0:10:Privileged Account:/:/bin/csh
       jcj:6k/7KCFRPNVXg:508:10:JC Javert:/usr2/jcj:/bin/csh

       In  this  example,  there  are  specific entries for users root and jcj, in case the Yellow Pages are temporarily out of service.  Alterna-
       tively, a user may need specific login information on a given system that differs from the information contained in the	Yellow	Pages  map
       for that user.  The user, john, will have his password entry in the Yellow Pages incorporated without change.  Anyone in the netgroup docu-
       mentation will have their password field disabled, and anyone else will be able to log in with their usual password, shell, and home direc-
       tory, but with a gecos field of Guest.

See Also
       chfn(1), finger(1), login(1), passwd(1), crypt(3), getpwent(3), group(5), adduser(8), vipw(8)


Check Out this Related Man Page

PASSWD(5)							   File formats 							 PASSWD(5)

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 superuser 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 output or batch jobs to the GCOS machine. The gcos field in the password file was a place to stash the information 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 chang- ing 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)

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