newgrp(1)

NAME

     newgrp - log in to a new group

SYNOPSIS

  Command
     /usr/bin/newgrp [ -| -l] [group]

  sh Built-in
     newgrp [argument]

  ksh Built-in
     *newgrp [argument]

DESCRIPTION

  Command
     The newgrp command logs a user into a new group by  changing
     a  user's  real  and  effective  group  ID. The user remains
     logged in and the current directory is unchanged. The execu-
     tion  of newgrp always replaces the current shell with a new
     shell, even if the command terminates with an error (unknown
     group).

     Any variable that is not exported is reset to  null  or  its
     default  value. Exported variables retain their values. Sys-
     tem variables (such as PS1, PS2, PATH, MAIL, and HOME),  are
     reset  to  default  values unless they have been exported by
     the system or the user. For example, when a user has a  pri-
     mary  prompt string (PS1) other than $ (default) and has not
     exported PS1, the user's PS1 will  be  set  to  the  default
     prompt  string  $,  even if newgrp terminates with an error.
     Note that the shell command export (see sh(1) and set(1)) is
     the  method  to  export  variables so that they retain their
     assigned value when invoking new shells.

     With no operands and  options,  newgrp  changes  the  user's
     group  IDs  (real and effective) back to the group specified
     in the user's password file entry. This is a way to exit the
     effect of an earlier newgrp command.

     A password is demanded if the group has a password  and  the
     user  is  not listed in /etc/group as being a member of that
     group. The only way to create a password for a group  is  to
     use   passwd(1),  then  cut  and  paste  the  password  from
     /etc/shadow to /etc/group. Group  passwords  are  antiquated
     and not often used.

  sh Built-in
     Equivalent  to  exec   newgrp    argument   where   argument
     represents the options and/or operand of the newgrp command.

  ksh Built-in

     Equivalent to exec to/bin/newgrp   argument  where  argument
     represents the options and/or operand of the newgrp command.

     On this man page, ksh(1) commands that are preceded  by  one
     or  two * (asterisks) are treated specially in the following
     ways:

     1. Variable assignment lists preceding the command remain in
        effect when the command completes.

     2. I/O redirections are  processed  after  variable  assign-
        ments.

     3. Errors cause a script that contains them to abort.

     4. Words, following a command preceded by ** that are in the
        format  of  a  variable assignment, are expanded with the
        same rules as a  variable  assignment.  This  means  that
        tilde substitution is performed after the = sign and word
        splitting and file name generation are not performed.

OPTIONS

     The following option is supported:

     -l | -
           Change the environment to what would  be  expected  if
           the  user  actually logged in again as a member of the
           new group.

OPERANDS

     The following operands are supported:

     group A group name from the group database or a non-negative
           numeric  group ID. Specifies the group ID to which the
           real and effective group IDs will be set. If group  is
           a  non-negative numeric string and exists in the group
           database as  a  group  name  (see  getgrnam(3C)),  the
           numeric  group ID associated with that group name will
           be used as the group ID.

     argument
           sh and ksh only. Options and/or operand of the  newgrp
           command.

ENVIRONMENT VARIABLES

     See environ(5) for descriptions of the following environment
     variables that affect the execution of newgrp: LANG, LC_ALL,
     LC_CTYPE, LC_MESSAGES, and NLSPATH.

EXIT STATUS

     If  newgrp  succeeds  in  creating  a  new  shell  execution
     environment,  whether  or  not  the group identification was
     changed successfully, the  exit  status  will  be  the  exit
     status  of the shell. Otherwise, the following exit value is
     returned:

     >0    An error occurred.

FILES

     /etc/group
           system's group file

     /etc/passwd
           system's password file

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|
    | Interface Stability         | Standard                    |
    |_____________________________|_____________________________|

SEE ALSO

     login(1), ksh(1),  set(1),  sh(1),  intro(3),  getgrnam(3C),
     group(4), passwd(4), attributes(5), environ(5), standards(5)