EXPORT(1P) POSIX Programmer's Manual EXPORT(1P)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 correspond‐
ing to the specified names, which shall cause them to be in the envi‐
ronment 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 IEEE Std 1003.1-2001, 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
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-fileunset 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 implemen‐
tations. 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
Special Built-In Utilities
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .
IEEE/The Open Group 2003 EXPORT(1P)
