PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

NAME

       export — set the export attribute for variables

SYNOPSIS

       export name[=word]...

       export -p

DESCRIPTION

       The  shell  shall  give the export attribute to the variables corresponding to the specified names, which
       shall cause them to be in the environment of subsequently executed commands. If the name of a variable is
       followed by =word, then the value of that variable shall be set to word.

       The export special built-in shall support the Base Definitions  volume  of  POSIX.1‐2017,  Section  12.2,
       Utility Syntax Guidelines.

       When  -p  is  specified,  export  shall write to the standard output the names and values of all exported
       variables, in the following format:

           "export %s=%s\n", <name>, <value>

       if name is set, and:

           "export %s\n", <name>

       if name is unset.

       The shell shall format the output, including the proper use of  quoting,  so  that  it  is  suitable  for
       reinput to the shell as commands that achieve the same exporting results, except:

        1. Read-only variables with values cannot be reset.

        2. Variables  that  were  unset  at  the time they were output need not be reset to the unset state if a
           value is assigned to the variable between the time the state was saved and  the  time  at  which  the
           saved output is reinput to the shell.

       When no arguments are given, the results are unspecified.

OPTIONS

       See the DESCRIPTION.

OPERANDS

       See the DESCRIPTION.

STDIN

       Not used.

INPUT FILES

       None.

ENVIRONMENT VARIABLES

       None.

ASYNCHRONOUS EVENTS

       Default.

STDOUT

       See the DESCRIPTION.

STDERR S

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES

       None.

EXTENDED DESCRIPTION

       None.

EXIT STATUS

        0    All name operands were successfully exported.

       >0    At least one name could not be exported, or the -p option was specified and an error occurred.

CONSEQUENCES OF ERRORS

       Default.

       The following sections are informative.

APPLICATION USAGE

       Note that, unless X was previously marked readonly, the value of "$?" after:

           export X=$(false)

       will  be  0 (because export successfully set X to the empty string) and that execution continues, even if
       set -e is in effect. In order  to  detect  command  substitution  failures,  a  user  must  separate  the
       assignment from the export, as in:

           X=$(false)
           export X

EXAMPLES

       Export PWD and HOME variables:

           export PWD HOME

       Set and export the PATH variable:

           export PATH=/local/bin:$PATH

       Save and restore all exported variables:

           export -p > temp-file
           unset a lot of variables
           ... processing
           . temp-file

RATIONALE

       Some  historical  shells  use  the no-argument case as the functional equivalent of what is required here
       with -p.  This feature was left unspecified because it is not historical practice in all shells, and some
       scripts may rely on the now-unspecified results on their implementations.  Attempts  to  specify  the  -p
       output  as  the  default case were unsuccessful in achieving consensus.  The -p option was added to allow
       portable access to the values that can be saved and then later restored using; for example, a dot script.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Section 2.14, Special Built-In Utilities

       The Base Definitions volume of POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee  document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                        EXPORT(1POSIX)