xenial (1) export.1posix.gz

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       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
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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.1‐2008, 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
       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
       Zero.


CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.


APPLICATION USAGE
       None.


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.1‐2008, Section 12.2, Utility Syntax Guidelines


       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 .

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       https://www.kernel.org/doc/man-pages/reporting_bugs.html .