use strict;
use warnings;

my $str = 'Lee Morgan : 20
Clifford Brown : 3
Freddie Hubbard : 6
';

my @data = map {[ split /\s+:\s+/, $_]} split /\n/, $str;

for (sort { $a->[1] <=> $b->[1] } @data) {
    print join( ' : ', @$_ ), $/;
}

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