#!/usr/bin/perl -w
use stritct;

my $c1 = 'system("touch /tmp/test1.txt")';  
my $c2 = 'system("touch /tmp/test2.txt")';  

#used as string (Dangerous!!!)
eval $c1;

#used as block (ok)
eval {$c2};  # <- gives a useless use of private variable in void context.