use strict;
use warnings;

my ( @header, %hash );
my @files = qw/File1.txt File2.txt/;
local $, = "\n";

for my $file (@files) {
	open my $fhIN, '<', $file or die $!;

	while ( my $line = <$fhIN> ) {
		my @columns = split ' ', $line;

		if ( $. == 1 ) {
			@header = @columns;
		}
		else {
			push @{ $hash{ $header[$_] } }, $columns[$_] for 1 .. $#columns;
		}
	}

	close $fhIN;

	for my $i ( 1 .. $#header ) {
		open my $fhOUT, '>', "$file\_$header[$i].txt" or die $!;
		print $fhOUT @{ $hash{ $header[$i] } };
		close $fhOUT;
	}

	undef %hash;
}