using the below 'while' loop I expect the output to be: a is car and b is tree
rather getting the one which I mentioned as 'o/p'. I am not very sure about eval, how it works, so pls explain and correct me where I have gone wrong.
Last edited by royalibrahim; 12-02-2008 at 05:23 AM..
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)
Hi,
I have snippet like the following
x="1"
prompt1="hi"
if I say
eval echo \$prompt$x then it is giving o/p "hi"
if I say `eval echo \$prompt$x` here it is giving 1 !
if I add one more escape character i.e.
`eval echo \\$prompt$x` then it is giving "hi"
Can you please... (3 Replies)
I am trying to expand the variable $user in my alias command and tried
several variations of eval but can't seem to get it to work.
The end result should be either:
oracle_user='sudo su - oracle ' or oracle_user='sudo su - oracle1 '
user=$(grep '^oracle:' /etc/passwd | cut... (5 Replies)
hi all,
Am trying to add some code to a ksh script and i dont understand how an eval function is used :
_var=$1
_conceal=$2
eval _val=\$${_var}
can someone shed some light on what the eval function in the above context means/does ??
thanks. (4 Replies)
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)
Hello All,
Since my variables are nested I use eval to populate the data.
I have an ambiguity here when eval is used along with &
say I have the below variable
url="www.unix.com" , this come from function call as argument.
I want to take this into another variable say... (6 Replies)
Alzabo::ChangeTracker(3pm) User Contributed Perl Documentation Alzabo::ChangeTracker(3pm)NAME
Alzabo::ChangeTracker - Saves a set of changes as callbacks that can be backed out if needed
SYNOPSIS
use Alzabo::ChangeTracker;
my $x = 0;
my $y = 1;
sub foo
{
my $tracker = Alzabo::ChangeTracker->new;
$tracker->add( sub { $x = 0; } );
$x = 1;
bar();
eval { something; };
$tracker->backout if $@;
}
sub bar
{
my $tracker = Alzabo::ChangeTracker->new;
$tracker->add( sub { $y = 1; } );
$y = 2;
}
DESCRIPTION
The trick ...
We only want to have one object of this type at any one time. In addition, only the stack frame that created it should be able to clear it
(except through a backout). Why? Here's an example in pseudo-code to help explain it:
sub foo
{
create a tracker;
store some change info in the tracker;
call sub bar;
store some change info in the tracker;
# point Y
clear changes in tracker;
}
sub bar
{
create a tracker; # internally, we really just increment our stack count
store some change info in the tracker;
clear changes in tracker; # point X
}
If at point X we were to really clear out the changes, even the changes just from sub bar, we'd have a problem. Because if at point Y,
things go to hell and we want to back out the changes, we want to back out the changes from sub foo _AND_ sub bar. However, if bar is also
an entry point we want to be able to track changes in bar and clear them from bar.
AUTHOR
Dave Rolsky, <autarch@urth.org>
perl v5.8.8 2007-12-23 Alzabo::ChangeTracker(3pm)