Your sort operator needs to impose a lexicographic ordering on the lists defined by your "paths", as in this example:
#!/usr/bin/perl
use strict;
use warnings;
# parse the paths into lists
my @data;
while ( <DATA> ) {
chomp;
push @data, [ split m:/:, $_ ];
}
sub compare_lists_lexicographically {
# make copies of the input lists
my @left = @$a;
my @right = @$b;
# chew threw the lists until
# a) we discover they're different lengths, or
# b) the elements are different, or
# c) neither
while ( 1 ) {
if ( !@left && !@right ) {
# ran out at the same time: they're equal
return 0;
}
elsif ( !@left ) {
# left is shorter than right: left is first
return -1;
}
elsif ( !@right ) {
# right is shorter than left: right is first
return 1;
}
else {
# check the next element from each list
my ( $l, $r ) = ( shift @left, shift @right );
# NB: use < if fields are numeric, lt otherwise
if ( $l < $r ) {
# next element of left comes first
return -1;
}
elsif ( $r < $l ) {
# next element of right comes first
return 1;
}
# else equal, keep checking
}
}
}
# display the output
printf "%s\n", join '/', @$_ for sort compare_lists_lexicographically
+@data;
__DATA__
0/1/2/3
0
0/4/5/6
0/4
0/1
0/1/2
0/4/5
0/10/111/145
0/10/111
0/10
HTH,
--athomason
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