use strict;
use warnings;

my (@data, %identifier);

while (<DATA>) {
    chomp; @_ = split /\s+/, $_, 6;
    push @data, [@_];
    $identifier{$_[0]} = $data[-1]; # Index for first field
}

# Sort on multiple fields, in this case fifth and first...
print "@$_\n" for sort {$a->[4] cmp $b->[4] || $a->[0] <=> $b->[0]} @data;

__DATA__
1 1023 T C cc Item 1
2 1560 T C aa Item 2
3 9102 T C bb Item 3
4 11222 T C ff Item 4
7 13456 T C bb Item 7