use strict;
use warnings;

use Text::CSV;

EXTRACT_FIRST_COLUMN(my $TEMPCSV = 'C:\temp\part1.csv', my $TEMPTXT = 
+'TEMP_AM.txt', my $FINALCSV = 'C:\temp\OUT.CSV');
EXTRACT_FIRST_COLUMN(my $TEMPCSV = 'C:\temp\part2.csv', my $TEMPTXT = 
+'TEMP_CA.txt', my $FINALCSV = 'C:\temp\OUT2.CSV');

sub EXTRACT_FIRST_COLUMN {
        my $csv = Text::CSV->new();
        open (FILE,">","$TEMPTXT");
        open (CSV, "<", $TEMPCSV);
        while (<CSV>) {
                if ($csv->parse($_)) {
                        my @column = $csv-> fields();
                        print FILE "$column[0]\n";
                } else {
                        #my err = $csv->error_input;
                        print "ERROR: Failed to parse line: $err";
                }
        }
        close (FILE);

        open (OUTPUT2,">","$FINALCSV");
        my $file = $TEMPTXT;
        open (my $FH, "<", $file) or die $!;
        while (<$fh>) {
                my $uri = $_;
                $uri =~ s/\s+//g;
                my ($name, $aliases, $addrtype, $length, @addrs) = get
+hostbyname $uri;
                my ($w,$x,$y,$z) = unpack('C4',$addr[0]);
                print OUTPUT2 "$w.$x.$y.$z\n";
        }
        close (OUTPUT2);
}
sub EXTRACT_FIRST_COLUMN();
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"my" variable $TEMPCSV masks earlier declaration in same scope at sub.pl line 9.
"my" variable $TEMPTXT masks earlier declaration in same scope at sub.pl line 9.
"my" variable $FINALCSV masks earlier declaration in same scope at sub.pl line 9.
Global symbol "$err" requires explicit package name at sub.pl line 21.
Global symbol "$fh" requires explicit package name at sub.pl line 29.
Global symbol "@addr" requires explicit package name at sub.pl line 33.
Execution of sub.pl aborted due to compilation errors.