For 'THE PROBLEM' you might want to consider using a loop, with a regex test for the files you want - a suggestion that infers from your text that the $from directory may contain non-.txt files.

#!/usr/bin/perl -w
use strict;
# 1190936

my @sourcefiles = <DATA>;

for $_(@sourcefiles) {
    if ($_ =~ /.+?\.txt/ ) {
    # process it here -- simulated by;
    print $_;
    } else {
            next;
    }
}

__DATA__
foo.bar
bar.txt
baz.bat
blivitz.txt;
nottext
and
somethingelse.txt
[download]

Rewriting LN 5 to obtain data from your source directory is left as a (trivial) exercise -- once you do some reading, using perldoc open, for example.

execution:

C:\1190936.pl
bar.txt
blivitz.txt;
somethingelse.txt
[download]