Lemme see if I understand what you're doing.

#!/usr/local/bin/perl

use strict;
use warnings;

## Declare variables and assign initial variables
my $in_file = "d:\\code\\temp files\\epropr_clean.txt";
my $out_file = "d:\\code\temp files\\epropr_parsed.txt";

## Open input file and assign to @records
my @records;
open IN_FILE, $in_file || die "Couldn't open $in_file: $!\n";
push @records, split(/:/, $_) while <IN_FILE>;
close IN_FILE;

shift @records;
my $arraylength = @records;

## Check array contents
my $count = 0;
/PROJ .{3}/ && $count++ for @records;
print $count, $/;

## Determine number of items in @record and place in @rec_array
my ($record, $curr_index) = ('', 0);
while ($curr_index < $arraylength) {

    my $num_recs = 29;
    if ($records[$curr_index + 1] =~ /Sup/) {
        $num_recs = 20;
    } elsif (grep { $records[$curr_index + 5] =~ /$_/ } qw(1LT 2LT CPT
+ MAJ LTC COL)) {
        $num_recs = 28;
    } 
    
    push @rec_array, @records[0 .. $num_recs - 1];
    $record = join(';', $record, splice(@records, 0, scalar(@rec_array
+));
    
    $curr_index += $num_recs;
    print "$num_recs - $curr_index\n";
}
[download]

All that's happening is that you're moving over elements from @record to @rec_array, then removing them from @record and moving them, joined by ';', to $record. What purpose does this serve?

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