DB<100> $path='var1/var2/var3'             # input
 => "var1/var2/var3"

  DB<102> @path=split /\//,$path             # extract path
 => ("var1", "var2", "var3")

  DB<103> $hash_ref->{var1}{var2}{var3}=42   # init nested test-hash 
 => 42

  DB<104> $node=$hash_ref                    # set start
 => { var1 => { var2 => { var3 => 42 } } }

  DB<105> $node=$node->{$_} for @path        # walk down path
 => ""

  DB<106> $node                              # check result
 => 42
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HTH! =)

You've partially lost me with that answer.

What if I may have a variable number of variables..

program.pl var1
program.pl var1/var2
program.pl var1/var2/var3
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etc? Is there a programatic way to read N variables into the reference?

I've changed my code to be less terse and hopefully better understandable step by step.

> What if I may have a variable number of variables..

you can put a unlimited anount of elements into '$path' and it will work as long as the intermediate values really exist within the nested hashes (otherwise the result is undef).

> Is there a programatic way to read N variables into the reference?

??? what do you mean here with "reference"?

Cheers Rolf

( addicted to the Perl Programming Language)

Data::Diver

As you're reading from the commandline, you'll probably want either a way to warn of invalid keys or, perhaps, ignore them. The following does the latter.

A valid list of keys:

$ perl -Mstrict -Mwarnings -E '
    my %x = ( a => { b => { d => 4, e => 5 }, c => 3 } );
    my $y = \%x;
    for (split /\// => $ARGV[0]) {
        last unless ref $y;
        $y = $y->{$_};
    }
    say $y if defined $y;
' a/b/e
5
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A partially valid list of keys:

$ perl -Mstrict -Mwarnings -E '
    my %x = ( a => { b => { d => 4, e => 5 }, c => 3 } );
    my $y = \%x;
    for (split /\// => $ARGV[0]) {
        last unless ref $y;
        $y = $y->{$_};
    }
    say $y if defined $y;
' a/c/e
3
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An invalid list of keys:

$ perl -Mstrict -Mwarnings -E '
    my %x = ( a => { b => { d => 4, e => 5 }, c => 3 } );
    my $y = \%x;
    for (split /\// => $ARGV[0]) {
        last unless ref $y;
        $y = $y->{$_};
    }
    say $y if defined $y;
' a/d/e
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