Change your approach. NEVER use undeclared variables. There is an option "set -o nounset" if I remember correctly.
You should have something like this:
Last edited by vgersh99; 10-01-2009 at 05:48 PM..
Reason: code tags, PLEASE!
Hi,
Command "chfn" can be used to change finger information.. can anybody tell me how to unset i mean reset the same finger information.
Thanks in advance,
Chanakya (3 Replies)
Hi All,
May be this is a very simple question...
$ b=8
$ readonly b
$ echo $b
8
$ b=90
-bash: b: readonly variable
$ unset b
-bash: unset: b: cannot unset: readonly variable
I m not able to change the readonly mode of variable b
Please help me out..
Thanks
Nidhi (2 Replies)
Hi All,
Is there any way to check exit status of unset variables?
In the following code PathX is not set and the script terminates without checking exit status.
#!/bin/bash
Path="/tmp/log"
cd ${PathX:?}
if ;then
echo "Exit Status : non zero"
else
echo "Exit Status :... (2 Replies)
Could someone please tell me how to unset your .bashrc? I have tried all of these. I can't find anything useful from google.
unset -f .bashrc
unset .bashrc (9 Replies)
I'm wondering, is the number of variables will affect execution time of my bash script or maybe affect the cpu workload, cpu memory, etc ?
If I create so many variables, should I unset each one of that variables after I used them or after I think they are no longer needed?
and if my script... (2 Replies)
I have a script to start/stop/restart the tomcat application. When we run the script first time i.e stop/start it set all env variables(DISTRIB_ID,NAME,TOMCAT_CFG,....etc),but when we restart the tomcat it is running in the same shell.....I need to set the variables when i restart the tomcat(in the... (1 Reply)
I have a script with a $PASSWORD variable. I unset it right after using it, just to minimize the chance it could be left around for a snooper. That worked just fine... until I used a password with a value of "P@ssw0rd" Now, unset (even with -f, even with the variable enquoted) tells me: unset:... (1 Reply)
I have tried to thoroughly search other threads before posting this question...
I have a shell script (bsh) that I'd like to "re-execute" if the user chooses to. Before the program is executed again the local variables (those set within the script) need to be unset. Is there a command that... (6 Replies)
Hi,
Can someone tell what is the path for "unset", I tried "which" command but getting below error
# which unset
/usr/bin/which: no unset in (/usr/lib/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin/:/root/bin) (9 Replies)
Discussion started by: stew
9 Replies
LEARN ABOUT SUSE
unset
UNSET(1P) POSIX Programmer's Manual UNSET(1P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
unset - unset values and attributes of variables and functions
SYNOPSIS
unset [-fv] name ...
DESCRIPTION
Each variable or function specified by name shall be unset.
If -v is specified, name refers to a variable name and the shell shall unset it and remove it from the environment. Read-only variables
cannot be unset.
If -f is specified, name refers to a function and the shell shall unset the function definition.
If neither -f nor -v is specified, name refers to a variable; if a variable by that name does not exist, it is unspecified whether a func-
tion by that name, if any, shall be unset.
Unsetting a variable or function that was not previously set shall not be considered an error and does not cause the shell to abort.
The unset special built-in shall support the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
Note that:
VARIABLE=
is not equivalent to an unset of VARIABLE; in the example, VARIABLE is set to "" . Also, the variables that can be unset should not be mis-
interpreted to include the special parameters (see Special Parameters ).
OPTIONS
See the DESCRIPTION.
OPERANDS
See the DESCRIPTION.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
None.
ASYNCHRONOUS EVENTS
Default.
STDOUT
Not used.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
0 All name operands were successfully unset.
>0 At least one name could not be unset.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
None.
EXAMPLES
Unset VISUAL variable:
unset -v VISUAL
Unset the functions foo and bar:
unset -f foo bar
RATIONALE
Consideration was given to omitting the -f option in favor of an unfunction utility, but the standard developers decided to retain histori-
cal practice.
The -v option was introduced because System V historically used one name space for both variables and functions. When unset is used without
options, System V historically unset either a function or a variable, and there was no confusion about which one was intended. A portable
POSIX application can use unset without an option to unset a variable, but not a function; the -f option must be used.
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 UNSET(1P)