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Full Discussion: Eval
Top Forums Shell Programming and Scripting Eval Post 302798443 by Corona688 on Wednesday 24th of April 2013 12:21:05 PM
Old 04-24-2013
Quote:
Originally Posted by rbatte1
Out of curiosity, why is eval considered evil Smilie.
Because it will evaluate any shell syntax you put into it, even things you didn't intend it to.

Imagine your program prompts for a user name, and someone types in $(rm -Rf ~/). Then that variable gets fed into an eval...

It is very, very difficult to make eval secure from this. Not impossible, but very hard. Much doublethink is required.

Further, it's often used by beginning programmers as a bridge or shoehorn when they don't know a better way to solve a problem.

Last edited by Corona688; 04-24-2013 at 01:34 PM..
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Padre::Task::Eval(3pm)					User Contributed Perl Documentation				    Padre::Task::Eval(3pm)

NAME
Padre::Task::Eval - Task for executing arbitrary code via a string eval SYNOPSIS
my $task = Padre::Task::Eval->new( prepare => '1 + 1', run => 'my $foo = sub { 2 + 3 }; $foo->();', finish => '$_[0]->{prepare}', ); $task->prepare; $task->run; $task->finish; DESCRIPTION
Padre::Task::Eval is a stub class used to implement testing and other miscellaneous functionality. It takes three named string parameters matching each of the three execution phases. When each phase of the task is run, the string will be eval'ed and the result will be stored in the same has key as the source string. If the key does not exist at all, nothing will be executed for that phase. Regardless of the execution result (or the non-execution of the phase) each phase will always return true. However, if the string eval throws an exception it will escape the task object (although when run properly inside of a task handle it should be caught by the handle). METHODS
This class contains now additional methods beyond the defaults provided by the Padre::Task API. COPYRIGHT &; LICENSE Copyright 2008-2012 The Padre development team as listed in Padre.pm. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module. perl v5.14.2 2012-06-27 Padre::Task::Eval(3pm)
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