SU(1)               RISC/os Reference Manual                SU(1)



NAME
     su, ssu - become super-user or another user

SYNOPSIS
     su [ - ] [ name [ arg ... ] ]
     ssu

DESCRIPTION
     With the su command it is possible to become another user
     without logging off.  The default user name is root (that
     is, super-user).  However, a user may not su to root unless
     that user is a member of group 0 (root) or is listed in
     /etc/su_people.  /etc/su_people is a configuration file that
     allows specified users to su to root without password or
     permissions checking.  The file must be owned by root (user
     0), belong to group root (group 0), and have permissions set
     to 0600 (read and write by owner only.) The system adminis-
     trator can give a user authorization to su to root by adding
     the user to group 0 in /etc/group, or to the corresponding
     database if NIS is enabled.  su authorization also can be
     given by the system administrator by creating the user with
     a basic group of root in etc/passwd or the corresponding NIS
     database.

     Otherwise, to use su the appropriate password must be sup-
     plied (unless the user already is root).  If the password is
     correct, su will execute a new shell with the real and
     effective user and group IDs set to that of the specified
     user.  If the line

          INITGROUPS=YES

     is specified in the file /etc/default/su, su will call
     initgroups(3C) to set the supplementary group list to that
     of the specified user.  The new shell will be the optional
     program named in the shell field of the specified user's
     password file entry [see passwd(4)] or /usr/bin/sh if none
     is specified [see sh(1)].  To restore normal user ID
     privileges, type an EOF character (CTRL-d) to the new shell.

     Any additional arguments given on the command line are
     passed to the program invoked as the shell.  When using pro-
     grams such as sh, an arg of the form -c string executes
     string via the shell and an arg of -r gives the user a res-
     tricted shell.

     The following statements are true only if the optional pro-
     gram named in the shell field of the specified user's pass-
     word file entry is like sh.  If the first argument to su is
     a -, the environment will be changed to what would be
     expected if the user actually logged in as the specified
     user.  This is done by invoking the program used as the



                        Printed 11/19/92                   Page 1

SU(1)               RISC/os Reference Manual                SU(1)



     shell with an arg0 value whose first character is -, thus
     causing first the system's profile (/etc/profile) and then
     the specified user's profile (.profile in the new HOME
     directory) to be executed.  Otherwise, the environment is
     passed along with the possible exception of $PATH, which is
     set to /sbin:/usr/sbin:/usr/bin:/etc for root.  Note that if
     the optional program used as the shell is /usr/bin/sh, the
     user's .profile can check arg0 for -sh or -su to determine
     if it was invoked by login or su, respectively.  If the
     user's program is other than /usr/bin/sh, then .profile is
     invoked with an arg0 of -program by both login and su.

     All attempts to become another user using su are logged in
     the file /var/adm/sulog, unless a different file is speci-
     fied using SULOG in /etc/default/su.

     ssu is the same as su -e -c root:

     -e   Do not reset the shell.

     -c   Execute extra arguments directly as commands instead of
          using the shell. If no arguments are given, use the
          shell.

EXAMPLES
     To become user bin while retaining your previously exported
     environment, execute:
          su bin

     To become user bin but change the environment to what would
     be expected if bin had originally logged in, execute:
          su - bin

     To execute command with the temporary environment and per-
     missions of user bin, type:
          su - bin -c "command args"

FILES
     /etc/passwd     system's password file
     /etc/profile    system's profile
     $HOME/.profile  user's profile
     /var/adm/sulog  default log file
     /etc/su_people  su configuration file
     /etc/default/su the default parameters that live here are:
                    SULOG:       If defined, all attempts to su
                                 to another user are logged in
                                 the indicated file.
                    CONSOLE:     If defined, all attempts to su
                                 to root are logged on the con-
                                 sole.
                    PATH:        Default path.
                    SUPATH:      Default path for a user invoking



 Page 2                 Printed 11/19/92

SU(1)               RISC/os Reference Manual                SU(1)



                                 su to root.
                    INITGROUPS:  Set supplementary group list to
                                 that of the specified user.

SEE ALSO
     env(1), login(1), sh(1) in the User's Reference Manual.
     passwd(4), profile(4), environ(5) in the Programmer's Refer-
     ence Manual.















































                        Printed 11/19/92                   Page 3