12-30-2002
Here is the small practical example. Just check it.
Just type them on the shell & observe the output.
$a=10 (I'm creating a shell variable named as 'a' with value 10.
$set (This will show the newly created variable & its value i.e. 'a=10').
$env (This will list some set of variables other than 'a=10'.
$export a (Now Execute this statement).
$set (Now this still shows a=10 other along with some more..)
$env (Now this will show a=10 also...).
I mean, 'set' display only local & un-exported variable.
Where as 'env' shows all global & exported variable variables.
When you think of why Global & local variables, the difference
comes when using shell scripts. In a shell script if you create a
a variable, then this will be visible only for the executing script.
But, in a script if you create a variable & if you export, then it will
become a global variable, so that all scripts will be able to see this
variable.
So, using export you are making a locallly visible varialbe a Globally visible variable.
You can also do this in a single shot.
ex:- $export a=10
$ env...shows the output.
Hope this makes some sense.
10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Hi All,
I'm trying to use the "echo" command in a korn shell script, and I want it to drop the trailing newline. Now I know that with the bash shell, the "-n" flag would solve this issue. Does anyone know how this can be done with the korn shell?
Cheers
Khoom (10 Replies)
Discussion started by: Khoomfire
10 Replies
2. Shell Programming and Scripting
Probably my first post, very new to shell scripting :)
Here is the script i am trying to modify to use function
# Script to create simple menus and take action according to that selected
# menu item
#
while :
do
clear
echo "-------------------------------------"
echo "... (2 Replies)
Discussion started by: replyramdas
2 Replies
3. Shell Programming and Scripting
Here is my script
#!/bin/bash
pwd
cd /var/lib/pgsql
Both "pwd" and "cd" are not executed is there any other way i can change the current working directory to /var/lib/pgsql pls help! (9 Replies)
Discussion started by: perk_bud
9 Replies
4. UNIX for Advanced & Expert Users
Can anyone explain this in detail ...
echo ${PWD#${PWD%/*/*}/}
Thanks in Advance (1 Reply)
Discussion started by: sakthi.abdullah
1 Replies
5. Solaris
Hi.. Everyone...
Kindly consider following :
login as: root
Using keyboard-interactive authentication.
Password:
Last login: Mon Nov 3 19:30:50 2008 from xxxxxxxxxxx
Sun Microsystems Inc. SunOS 5.10 Generic January 2005
You have new mail.
Sourcing //.profile-EIS.....
#
#
... (3 Replies)
Discussion started by: Reboot
3 Replies
6. Shell Programming and Scripting
I have entry in the my .profile like below, but still i see $PWD is not defied in my system
export PS1=$LOGNAME@`hostname`':'$PWD'>'
echo $PWD also gives me nothing, my env list also give no entry for PWD.Can someone help me setting PWD variable.
I use /bin/sh (9 Replies)
Discussion started by: yesmani
9 Replies
7. Homework & Coursework Questions
1. The problem statement, all variables and given/known data:
need to implement mkdir, chdir, mv, pwd
given a shell.cpp directory.cpp and some other files
this shell missing these commands, and i need to implement them inside the shell
2. Relevant commands, code, scripts,... (0 Replies)
Discussion started by: evantheking
0 Replies
8. Shell Programming and Scripting
echo '#!/usr/local/bin/expect' > sree_expt
echo "spawn passwd $User" >> sree_expt
echo 'expect "New password:"' >> sree_expt
echo send "$Password\r" >> sree_expt
echo 'expect "Re-enter new password:"' >> sree_expt
echo send "$Password\r" >> sree_expt
echo "expect eof" >> sree_expt
for... (0 Replies)
Discussion started by: sreedhargouda
0 Replies
9. AIX
currently, my samba login works just fine. i want my clients to use aix5.3 account to login to samba so they don't have to change samba pwd and aix pwd. i googled, and vi /usr/lib/smb.conf per some of knowledge base, but i could not get to work.
aix5.3 and samba 3.0.24.0
thanks in advace..... (2 Replies)
Discussion started by: tjmannonline
2 Replies
10. Shell Programming and Scripting
Hi there,
i was presented with a challenge that is beyond my current shell knowledge: how can you have a script that executed interactive will change your current working directory?
Example (under MacOS):
1. start Terminal and my current working directory is my home folder
2. execute a... (3 Replies)
Discussion started by: gigagigosu
3 Replies
EXPORT(P) POSIX Programmer's Manual EXPORT(P)
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 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
", <name>, <value>
if name is set, and:
"export %s
", <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 imple-
mentations. 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 Technol-
ogy -- 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(P)