solaris - newgrp (1)

     newgrp - log in to a new group

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

  sh Built-in
     newgrp [ argument ]

  ksh Built-in
     *
     newgrp [ argument ... ]

     SUNWcsu

  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.
     System 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
     primary  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  /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.

     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.

     The following operand is 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  associ-
                    ated with that group name will be used as the
                    group ID.

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

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

     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.

     /etc/group     system's group file

     /etc/passwd    system's password file

     login(1), ksh(1),  set(1),  sh(1),  intro(2),  getgrnam(3C),
     group(4), passwd(4), environ(5)