9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
anyone has any info on why this is complaining???
vivek@vivek-c5e55ef2e ~/TAC
$ zoneCounter=1
vivek@vivek-c5e55ef2e ~/TAC
$ optUsage1=23%
vivek@vivek-c5e55ef2e ~/TAC
$ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>"
-bash: syntax error... (13 Replies)
Discussion started by: vivek d r
13 Replies
2. Shell Programming and Scripting
anyone has any info on why this is complaining???
vivek@vivek-c5e55ef2e ~/TAC
$ zoneCounter=1
vivek@vivek-c5e55ef2e ~/TAC
$ optUsage1=23%
vivek@vivek-c5e55ef2e ~/TAC
$ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>"
-bash: syntax error... (1 Reply)
Discussion started by: vivek d r
1 Replies
3. HP-UX
Hello folk,
I'm trying to study HP-UX by myself. Now I'm reading some stuffs about how to get information about lunpath, lun and etc..
My problem is when I execute scsimgr like this:
# scsimgr get_info -H 0/1/2/0.149.0.255.10.11.0
old
new
if
Usage: scsimgr -o old_target_name -n... (1 Reply)
Discussion started by: alfastar
1 Replies
4. Shell Programming and Scripting
Hi all,
some small script with eval turned me to crazy.
my OS is linux
Linux s10-1310 2.6.16.53-0.8.PTF.434477.3.TDC.0-smp #1 SMP Fri Aug 31 06:07:27 PDT 2007 x86_64 x86_64 x86_64 GNU/Linux
below script works well
#!/bin/bash
eval ssh remotehost date
eval ssh remotehost ls
below... (1 Reply)
Discussion started by: summer_cherry
1 Replies
5. Shell Programming and Scripting
Hi.
I am trying to populate an array using eval in the background within a function. So this function will create a list of 3 character directories from SVN and store in an array. I want to call this function when the script starts in the background unknown to the user.
The problem is that... (2 Replies)
Discussion started by: jmiaebrown
2 Replies
6. Shell Programming and Scripting
Hi All,
I'm running some encrypted data through a script I wrote. In order to do this, I'm using eval to resolve some of my variables. At the moment, when I use eval to resolve, it strips out some of my encrypted values, and totally drops some others. For example if I have the value ab1"3 it drops... (1 Reply)
Discussion started by: Khoomfire
1 Replies
7. Shell Programming and Scripting
I try to get a number of elements in an array, using dynamic array name.
I need the array name to be dynamic.
The array name is constructed as 'inf_ln_$nmb', where $nmb is a file line number
So, say I have the arr 'inf_ln_4':
> for (( el=0; el<${#inf_ln_4}; el++ )); do
> echo "$el:... (1 Reply)
Discussion started by: alex_5161
1 Replies
8. Shell Programming and Scripting
I want to get a status code array for the commands in eval.
For example,
eval "ls abc; ls def; ls $HOME"
I want to get the status code for each ls command in eval. Is there any way to make it?
Thanks. (2 Replies)
Discussion started by: pankai
2 Replies
9. UNIX for Advanced & Expert Users
Dear All
I tried to follow the instruction in this link:
http://multiboot.solaris-x86.org/v/2.html
I created all these partitions as mentioned in the link above by using partition commander 9
Fist stage:
I installed XP in first partition (hda1)....success.
Second stage:
Install... (0 Replies)
Discussion started by: zillah
0 Replies
Perl::Critic::Policy::ErrorHandling::RequireCheckingRetuUserlContributed PPerl::Critic::Policy::ErrorHandling::RequireCheckingReturnValueOfEval(3)
NAME
Perl::Critic::Policy::ErrorHandling::RequireCheckingReturnValueOfEval - You can't depend upon the value of "$@"/"$EVAL_ERROR" to tell
whether an "eval" failed.
AFFILIATION
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION
A common idiom in perl for dealing with possible errors is to use "eval" followed by a check of $@/$EVAL_ERROR:
eval {
...
};
if ($EVAL_ERROR) {
...
}
There's a problem with this: the value of $EVAL_ERROR can change between the end of the "eval" and the "if" statement. The issue is object
destructors:
package Foo;
...
sub DESTROY {
...
eval { ... };
...
}
package main;
eval {
my $foo = Foo->new();
...
};
if ($EVAL_ERROR) {
...
}
Assuming there are no other references to $foo created, when the "eval" block in "main" is exited, "Foo::DESTROY()" will be invoked,
regardless of whether the "eval" finished normally or not. If the "eval" in "main" fails, but the "eval" in "Foo::DESTROY()" succeeds,
then $EVAL_ERROR will be empty by the time that the "if" is executed. Additional issues arise if you depend upon the exact contents of
$EVAL_ERROR and both "eval"s fail, because the messages from both will be concatenated.
Even if there isn't an "eval" directly in the "DESTROY()" method code, it may invoke code that does use "eval" or otherwise affects
$EVAL_ERROR.
The solution is to ensure that, upon normal exit, an "eval" returns a true value and to test that value:
# Constructors are no problem.
my $object = eval { Class->new() };
# To cover the possiblity that an operation may correctly return a
# false value, end the block with "1":
if ( eval { something(); 1 } ) {
...
}
eval {
...
1;
}
or do {
# Error handling here
};
Unfortunately, you can't use the "defined" function to test the result; "eval" returns an empty string on failure.
Various modules have been written to take some of the pain out of properly localizing and checking $@/$EVAL_ERROR. For example:
use Try::Tiny;
try {
...
} catch {
# Error handling here;
# The exception is in $_/$ARG, not $@/$EVAL_ERROR.
}; # Note semicolon.
"But we don't use DESTROY() anywhere in our code!" you say. That may be the case, but do any of the third-party modules you use have them?
What about any you may use in the future or updated versions of the ones you already use?
CONFIGURATION
This Policy is not configurable except for the standard options.
SEE ALSO
See thread on perl5-porters starting here: <http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2008-06/msg00537.html>.
For a nice, easy, non-magical way of properly handling exceptions, see Try::Tiny.
AUTHOR
Elliot Shank "<perl@galumph.com>"
COPYRIGHT
Copyright (c) 2008-2011 Elliot Shank.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license
can be found in the LICENSE file included with this module.
perl v5.16.3 2014-0Perl::Critic::Policy::ErrorHandling::RequireCheckingReturnValueOfEval(3)