PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR S | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

EXPORT(1P)                POSIX Programmer's Manual               EXPORT(1P)

PROLOG         top

       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         top

       export — set the export attribute for variables

SYNOPSIS         top

       export name[=word]...

       export −p

DESCRIPTION         top

       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.1‐2008, 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. If a
       variable assignment precedes the command name of export but that
       variable is not also listed as an operand of export, then that
       variable shall be set in the current shell execution environment
       after the completion of the export command, but it is unspecified
       whether that variable is marked for export.

OPTIONS         top

       See the DESCRIPTION.

OPERANDS         top

       See the DESCRIPTION.

STDIN         top

       Not used.

INPUT FILES         top

       None.

ENVIRONMENT VARIABLES         top

       None.

ASYNCHRONOUS EVENTS         top

       Default.

STDOUT         top

       See the DESCRIPTION.

STDERR S         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       Zero.

CONSEQUENCES OF ERRORS         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       None.

EXAMPLES         top

       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         top

       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         top

       None.

SEE ALSO         top

       Section 2.14, Special Built-In Utilities

       The Base Definitions volume of POSIX.1‐2008, Section 12.2, Utility
       Syntax Guidelines

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/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                 2013                          EXPORT(1P)

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