4.3BSD-UWisc/man/cat5/passwd.5

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



NAME
     passwd - password file

SYNOPSIS
     /etc/passwd

DESCRIPTION
     The _p_a_s_s_w_d file contains for each user the following infor-
     mation:

     name      User's login name - contains no upper case charac-
               ters and must not be greater than eight characters
               long.

     password  encrypted password

     numerical user ID
               This is the user's ID in the system and it must be
               unique.

     numerical group ID
               This is the number of the group that the user
               belongs to.

     user's real name
               In some versions of UNIX, this field also contains
               the user's office, extension, home phone, and so
               on.  For historical reasons this field is called
               the GCOS field.

     initial working directory
               The directory that the user is positioned in when
               they log in - this is known as the `home' direc-
               tory.

     shell     program to use as Shell when the user logs in.

     The user's real name field may contain `&', meaning insert
     the login name.

     The password file 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 pass-
     word field is null, no password is demanded; if the Shell
     field is null, /_b_i_n/_s_h is used.

     The _p_a_s_s_w_d file can also have line beginning with a plus
     (+), which means to incorporate entries from the yellow
     pages.  There are three styles of + entries: all by itself,
     + means to insert the entire contents of the yellow pages
     password file at that point; +_n_a_m_e means to insert the entry
     (if any) for _n_a_m_e from the yellow pages at that point;



Printed 12/27/86         1 February 1985                        1






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



     +@_n_a_m_e means to insert the entries for all members of the
     network group _n_a_m_e at that point.  If a + entry has a non-
     null password, directory, gecos, or shell field, they will
     overide what is contained in the yellow pages.  The numeri-
     cal user ID and group ID fields cannot be overridden.

EXAMPLE
     Here is a sample /_e_t_c/_p_a_s_s_w_d file:


          root:q.mJzTnu8icF.:0:10:God:/:/bin/csh
          tut:6k/7KCFRPNVXg:508:10:Bill Tuthill:/usr2/tut:/bin/csh
          +john:
          +@documentation:no-login:
          +:::Guest

     In this example, there are specific entries for users _r_o_o_t
     _t_u_t, in case the yellow pages are out of order.  The user
     will have his password entry in the yellow pages incor-
     porated without change; anyone in the netgroup _d_o_c_u_m_e_n_t_a_t_i_o_n
     will have their password field disabled, and anyone else
     will be able to log in with their usual password, shell, and
     home directory, but with a gecos field of _G_u_e_s_t.

     The password file resides in the /_e_t_c directory.  Because of
     the encrypted passwords, it has general read permission and
     can be used, for example, to map numerical user ID's to
     names.

     Appropriate precautions must be taken to lock the
     /_e_t_c/_p_a_s_s_w_d file against simultaneous changes if it is to be
     edited with a text editor; _v_i_p_w(8) does the necessary lock-
     ing.

FILES
     /etc/passwd

SEE ALSO
     getpwent(3), login(1), crypt(3), passwd(1), group(5),
     vipw(8), adduser(8)















Printed 12/27/86         1 February 1985                        2