@array = sort { $a->[0] cmp $b->[0] } @array; # ascending
#@array = sort { $b->[0] cmp $a->[0] } @array; # descending
[download]

Update:

for my $i ( 0 .. $#array ) isn't a very Perlish way of iterating over an array.

Both

for my $elem ( @array ) {
    print "$elem->[0]\n";
}
[download]

and

print "$_->[0]\n"
    for @array;
[download]

are considered more idiomatic.