Hello, victorz22. I am writing this in hopes that you actually want to get better at using Perl.

I've rewritten your script, but I had to guess at some of your intentions.

I pointedly avoided the use of modules so you could see the logic.

This is not how I would write the code. This is strictly for your learning benefit.

#!/usr/bin/perl
use strict;
use warnings;

# Using this array to simulate the input file (reduces code size)
my    @Inpbuf = 
(
    'old/path/to/some/file',
    'another/old/path/to/some/file',
     'one/more/old/path/to/some/file',
    'bad/cold/example/old/path/to/some/file',
);

# This is the old path
my    $Oldpat = 'old';

# This is the desired new path
my    $Newpat = 'new';

# This is a horrible way to specify the directory separator (reduces c
+ode size)
my    $Dirsep = "/";
my    $Dirrgx = quotemeta $Dirsep;

# Loop through the input and demonstrate two ways to perform the adjus
+tment
foreach my $inpbuf (@Inpbuf) {
    # Translation here so we can support future multiple translation l
+ogic
    my    $oldrgx = quotemeta $Oldpat;

    # This should produce unwanted results on fourth line of data
    my $tstbuf = $inpbuf;
    $tstbuf =~ s/$oldrgx/$Newpat/g;
    print "  Risky transation:  [$inpbuf] -> [$tstbuf]\n";
    
    # This probably has a higher rate of intended results
    my @inpelt = split /$Dirrgx/, $inpbuf;
    my @outelt = ();
    foreach my $inpelt (@inpelt)
    {
        my $outelt = $inpelt;
        $outelt =~ s/^$oldrgx$/$Newpat/;
        push @outelt, $outelt;
    }
    my $outbuf = join $Dirsep, @outelt;
    print "Proper translation:  [$inpbuf] -> [$outbuf]\n";
    print "\n";
}

exit;

__END__
[download]

My results:

P:\>chg10.pl
  Risky transation:  [old/path/to/some/file] -> [new/path/to/some/file
+]
Proper translation:  [old/path/to/some/file] -> [new/path/to/some/file
+]

  Risky transation:  [another/old/path/to/some/file] -> [another/new/p
+ath/to/some/file]
Proper translation:  [another/old/path/to/some/file] -> [another/new/p
+ath/to/some/file]

  Risky transation:  [one/more/old/path/to/some/file] -> [one/more/new
+/path/to/some/file]
Proper translation:  [one/more/old/path/to/some/file] -> [one/more/new
+/path/to/some/file]

  Risky transation:  [bad/cold/example/old/path/to/some/file] -> [bad/
+cnew/example/new/path/to/some/file]
Proper translation:  [bad/cold/example/old/path/to/some/file] -> [bad/
+cold/example/new/path/to/some/file]


P:\>
[download]