mkpath($homeDir, 0, 0077);
    chdir $homeDir;
        mkpath($tmpDir, 0, 0077);
    chdir $tmpDir;
    system qq{wget "$mainSite/$torrentSite"};
    open FILE, $torrentFile;
    open CMD, "ls *torrent |";
    close CMD;
        system qq{transmissioncli -ep --download-dir $homeDir/$tmpDir 
+ --uplimit number 0 --config-dir $homeDir/$tmpDir $torrent &};
            open CMD, "transmission-remote --list |";
            close CMD;
                system "transmission-remote -t 1 -S &";
[download]

You should ALWAYS verify that these system calls performed correctly before trying to use code that relies on their results.

    if (! -d $homeDir ) {
        print "Making $homeDir.\n";
        mkpath($homeDir, 0, 0077);
    }

    print "Entering $homeDir.\n";
    chdir $homeDir;

    if (! -d $tmpDir ) {
        print "Making $tmpDir.\n";
        mkpath($tmpDir, 0, 0077);
    }

    print "Entering $tmpDir.\n";
    chdir $tmpDir;
[download]

Why not just use one step:

    unless ( -d "$homeDir/$tmpDir" ) {
        print "Making $homeDir/$tmpDir.\n";
        my $err;
        eval {
            mkpath "$homeDir/$tmpDir", { verbose => 0, mode => 0077, e
+rror => \$err };
        };
        if ( $@ or @$err ) {
            die "mkpath failed because: ", $@ || @$err;
        }
    }

    print "Entering $homeDir/$tmpDir.\n";
    chdir "$homeDir/$tmpDir" or die "Cannot chdir to '$homeDir/$tmpDir
+' because: $!";
[download]

            eval $code or die $!;
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The $! variable will not have any useful information from eval.    You need to use the $@ variable instead.

    my @torrentFiles;
    open CMD, "ls *torrent |";
    while (my $line = <CMD>) {
        chomp $line;
        push @torrentFiles, $line;
    }
    close CMD;
[download]

Or just:

    my @torrentFiles = glob '*torrent';
[download]