is it possible to use eval to create constants in perl? i cannot seem to get anything to work, and my searches are turning up little to nothing. an example of what i am trying to do is this:
2 arrays:
array 1: 'FOOD','NUMBER','OS'
array 2: 'pizza','two','unix'
loop through the arrays and... (5 Replies)
Hi I need some major help with eval
I have a statement using eval:
read input
eval variable$input=”something”
Now I want to use the “variable$input” in some commands but I don't know how to call it without replacing the $input with the command line value (which I obviously can't do).
... (1 Reply)
I used the eval command in shell programming for assigning a value to a stored value of a variable.
Example:
VAR="Unix_Id"
eval $VAR="101"
eval echo $"$VAR"
How can i assign a value to a stored value of a variable in perl OR how i can write above code in Perl?
I need your help... (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)
Hi All,
I read the above written code (perl code) in another perl script and evaluates this code for each line of text file,but using exit statement in code make this not to work and i could not get the desired results. However if i use return it works fine. I just need to know why it doesn't... (1 Reply)
Can anyone tell me how to export a variable from one perl CGI script to another perl cgi script when using a redirect.
Upon running the login.pl the user is prompted to enter user name and password. Upon entering the correct credentials (admin/admin) the user is
redirected to welcome page.
My... (3 Replies)
Heya
I have modified $HOME/.config/user-dirs.dirs to my like and the variables are properly 'structured' (XDG_XY_DIR="$HOME/YZ").
Now since i wrote a script to do that part, i currently stuck at the part to create a new .gtk-bookmarks file.
Regarding code snippet: (bold part beeing... (2 Replies)
Discussion started by: sea
2 Replies
LEARN ABOUT MOJAVE
universal::require5.18
UNIVERSAL::require(3) User Contributed Perl Documentation UNIVERSAL::require(3)NAME
UNIVERSAL::require - require() modules from a variable
SYNOPSIS
# This only needs to be said once in your program.
require UNIVERSAL::require;
# Same as "require Some::Module"
my $module = 'Some::Module';
$module->require or die $@;
# Same as "use Some::Module"
BEGIN { $module->use or die $@ }
DESCRIPTION
If you've ever had to do this...
eval "require $module";
to get around the bareword caveats on require(), this module is for you. It creates a universal require() class method that will work with
every Perl module and its secure. So instead of doing some arcane eval() work, you can do this:
$module->require;
It doesn't save you much typing, but it'll make alot more sense to someone who's not a ninth level Perl acolyte.
Methods
require
my $return_val = $module->require or die $@;
my $return_val = $module->require($version) or die $@;
This works exactly like Perl's require, except without the bareword restriction, and it doesn't die. Since require() is placed in the
UNIVERSAL namespace, it will work on any module. You just have to use UNIVERSAL::require somewhere in your code.
Should the module require fail, or not be a high enough $version, it will simply return false and not die. The error will be in $@ as well
as $UNIVERSAL::require::ERROR.
$module->require or die $@;
use
my $require_return = $module->use or die $@;
my $require_return = $module->use(@imports) or die $@;
Like "UNIVERSAL::require", this allows you to "use" a $module without having to eval to work around the bareword requirement. It returns
the same as require.
Should either the require or the import fail it will return false. The error will be in $@.
If possible, call this inside a BEGIN block to emulate a normal "use" as closely as possible.
BEGIN { $module->use }
SECURITY NOTES
UNIVERSAL::require makes use of "eval STRING". In previous versions of UNIVERSAL::require it was discovered that one could craft a class
name which would result in code being executed. This hole has been closed. The only variables now exposed to "eval STRING" are the
caller's package, filename and line which are not tainted.
UNIVERSAL::require is taint clean.
COPYRIGHT
Copyright 2001, 2005 by Michael G Schwern <schwern@pobox.com>.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
See http://www.perl.com/perl/misc/Artistic.html
AUTHOR
Michael G Schwern <schwern@pobox.com>
Now maintained by Neil Bowers (NEILB).
SEE ALSO
Module::Load, "require" in perlfunc, <http://dev.perl.org/rfc/253.pod>
perl v5.18.2 2013-09-27 UNIVERSAL::require(3)