Some general observations on the code:

• if (ref($replacement) eq 'ARRAY' && length $replacement > 1) { ... }

  length always operates on a string or stringized expression. A stringized reference looks something like "ARRAY(0x123abc)", so the expression length $replacement > 1 will always be true if $replacement is a reference.

  Win8 Strawberry 5.8.9.5 (32)  Fri 08/05/2022 17:16:08
  C:\@Work\Perl\monks
  >perl
  
  use strict;
  use warnings;
  
  my $arrayref = [ ];  # ref. to zero length array
  
  print "$arrayref \n";
  print "length non-zero \n" if length $arrayref > 1;
  
  ^Z
  ARRAY(0x613824)
  length non-zero
  [download]

  The number of elements of an array is found by evaluating the array in scalar context (update: see Context and subsequent topics in perldata) or, in newer Perls (5.12+), by the keys built-in evaluated in scalar context (check your documentation).

  Win8 Strawberry 5.30.3.1 (64)  Fri 08/05/2022 17:39:54
  C:\@Work\Perl\monks
  >perl
  
  use strict;
  use warnings;
  
  my $arrayref = [ 9, 8, ];  # ref. to NON-zero length array
  
  printf "number of elements of referenced array: %d \n", scalar      @$
  +arrayref;
  printf "number of elements of referenced array: %d \n", 0 +         @$
  +arrayref;
  printf "number of elements of referenced array: %d \n", scalar keys @$
  +arrayref;
  print  "number of elements > 1 \n" if @$arrayref > 1;
  print  "number of elements > 1 \n" if keys @$arrayref > 1;
  
  ^Z
  number of elements of referenced array: 2
  number of elements of referenced array: 2
  number of elements of referenced array: 2
  number of elements > 1
  number of elements > 1
  [download]

  (Update: Just to be clear, a proper re-statement of the condition expression would be
      if (ref($replacement) eq 'ARRAY' && @$replacement > 1) { ... }
  The > numeric comparison imposes scalar context.)

• if ($choice eq 'y' || 'Y') { ... }

  This condition evaluates as "if $choice is 'y' or if the string 'Y' is true", i.e., it's always true because 'Y' is always true. See What is true and false in Perl?

  An effective case-insensitive conditional test would be
      if (lc($choice) eq 'y') { ... }