use strict;
use warnings;
use Text::CSV;

my ( $csvFileName, @csvLines ) = 'FileName.csv';
my $csv = Text::CSV_XS->new( { binary => 1, auto_diag => 2 } )
  or die "Cannot use CSV: " . Text::CSV->error_diag();

open my $csvfh, '<', $csvFileName or die $!;

# Get first line (array reference to parsed column names)
my $columnNames = $csv->getline($csvfh);

# $row contains an array reference to the parsed csv line
while ( my $row = $csv->getline($csvfh) ) {
	push @csvLines, $row;
}
close $csvfh;

# $a->[3] dereferences the array reference to get the third element
@csvLines = sort { $a->[3] <=> $b->[3] } @csvLines;

# Add column names array reference to beginning of array
unshift @csvLines, $columnNames;

$csv->eol("\n");

# Print the sorted csv lines to a file
open $csvfh, '>', "sorted_$csvFileName" or die $!;
$csv->print( $csvfh, $_ ) for @csvLines;
close $csvfh;