Perl: Comparing the contents of one file with those of several others - regex

Question

I have to read a CSV file (TEST.csv) with contents of this sort:
Sl.No, Label, Customer1, Customer2, Customer3...
1, label1, Y, N, Y...
2, label2, N, Y, Y...
...
and retrieve only the labels marked as "Y" for every "customer", into an external file for that "customer". With some help from SO members in another question, I managed to desist from getting lost in a maze of nested data structures, and am using the construct below. Here, I'm copying the labels marked as "Y" to a temp file _temp.h for the corresponding customers.
Now, the actual "external file" I need to write does not just have the labels, but is a copy of an "internal file" internal.h, which has data in this form:
/*...comments*/
#define header_label1 val1;
#define header_label2 val2;
...
For example, I might have a line #define ABC_Comp1_X_H_CompDes1 value. If the label Comp1_CompDes1 is present in the temp file I create for customer 1, then the line above is copied into the final external file for customer 1.
The following code is the one I'm using. However, this throws an error "Global symbol "%tempLines" requires explicit package name" for the line marked "HERE", though I'm not using a hash, and also of syntax errors in the next couple of lines w.r.t. the curly braces.
Any guidance as to the reason behind these errors would be highly appreciated.
use strict;
use warnings;
use File::Slurp;
use Data::Dumper;
my $numCustomers;
my $intHeaderFile = "internal.h";
open(my $fh, "<", "TEST.csv") or die "Unable to open CSV, $!";
open(my $infh, "<", $intHeaderFile) or die "Cannot open $intHeaderFile, $!";
my #headerLines = read_file($intHeaderFile);
chomp( my $header = <$fh> );
my #names = split ",", $header;
$numCustomers = scalar(#names) - 2;
print "\nNumber of customers : $numCustomers\n";
my #customerNames;
for(my $i = 0; $i < $numCustomers; $i++)
{
push #customerNames, $names[$i + 2];
}
my #tempHandles;
my #handles;
my #tempfiles;
my #files;
for(my $i = 0; $i < $numCustomers; $i++)
{
my $custFile = "customer".$i."_external.h";
open my $fh, '>', $custFile or die "$custFile: $!";
push #handles, $fh;
push #files, $custFile;
my $tempFile = "customer".$i."_temp.h";
open my $fh1, '+>', $tempFile or die "$tempFile: $!";
push #tempHandles, $fh1;
push #tempfiles, $tempFile;
}
while (<$fh>)
{
chomp;
my $nonIncLine = $_;
my #fields = split ",", $nonIncLine;
next if $. == 1;
for(my $i = 0; $i < $numCustomers; $i++)
{
print { $tempHandles[$i] } $fields[1], "\n" if 'Y' eq $fields[ $i + 2 ];
}
}
for(my $i = 0; $i < $numCustomers; $i++)
{
my #tempLines = read_file($tempfiles[$i]);
print #tempLines;
foreach my $headerLine(#headerLines)
{
if (grep { $headerLine =~ /$_/} #tempLines ) #HERE
{
print { $handles[$i] } $headerLine, "\n";
}
}
unlink($tempfiles[$i]);
}