Monks I am seeking your help once again. I apologize in advance if I am just over looking something very simple, but I just can't figure out what I am doing wrong here. I am working on a script that first reads some data into a hash. Then it reads some data from a flat txt benchmark file into another hash. From there I am printing a report that essentially just compares the hashes to print the data. However I am getting an error that one of my variables needs to an explicit package name and I can;t figure out why. Here is the code. I have tried to strip it down to just the pertinent stuff. 
#!/usr/local/bin/perl -w
use strict;
use vars qw($opt_m);
use Getopt::Std;

my ($today) = &finder();
if ($script_mode eq 'normal') {
        my ($yesterday) = &read_benchmark();
        &write_benchmark();
        &print_report();
} else {
        &write_benchmark();
}

sub finder {
        my %today;
        open (IN, "< todays data") or die "$!";
        while (<IN>) {
                chomp;
                $today{$_}++;
        }
        close (IN);
        return \%today;
}

sub read_benchmark {
        my %yesterday;
        open (BENCH, "< benchmark.txt") or die "$!";
        while (<BENCH>) {
                chomp;
                $yesterday{$_}++;
        }
        close (BENCH);
        return \%yesterday;
}

sub write_benchmark {
        open (BENCH, "> benchmark.txt") or die "$!";
        foreach (sort keys %$today) {
                print BENCH "$_\n";
        }
        close (BENCH);
        chmod(0640, "benchmark.txt") or die "$!";
        return;
}

sub print_report {
        foreach (sort keys %$today) {
            print LOG "$_\n" unless exists $yesterday->{$_};
        }
        foreach (sort keys %$yesterday) {
                print LOG "$_\n" unless exists $today->{$_};
        }
        print LOG "End of Report.\n";
        return;
}

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The Error message I get is. Global symbol "$yesterday" requires explicit package name at ./daily10 line 115. Line 115 is where I try to use $yesterday->{$_}. Now I am guessing that %yesterday isn't accessible because it is returned to that if statement, but the other subs that access are within that if statement too. I guess by declaring the variable in use vars that would probably work, but I don't understand why it isn;t working here. Any help is appreciated. Thanks.

In reply to Problem Declaring Variable by PrimeLord

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