Actual Location: \\Server\Volume\Text\001\ABC001.txt

Server Location Variable, $A contains \\Server\Volume\LoadFiles

FilePath Variable, $B contains E:\Volume\Text\001\ABC001.txt

I want to modify $A and store the replacement value for $B so that $A\$BPrime would give me the file.

$BMinus in this case should be E:\
$BPrime is Text\001\ABC001.txt
$A is \\Server\Volume

What I have is this: I would love to get some feedback as to what I might have done differently or alternatives. Cause this still seems a bit cludgy.

my $BMinus = substr ($B, 0, (index ($B,&CheckFile(\$A,$B)) - 1));

sub CheckFile {
    my ($P_ref,$T) = @_;
    &CrawlForward($P_ref,\$T);
    while (!(-s "$$P_ref\\$T") || (-s $T)) {
        $$P_ref =~ s/\A(.+)\\[^\\]+\z/$1/;
        &CrawlForward($P_ref,\$T);
    }
    return $T;
}
sub CrawlForward {
    my ($C_ref,$T_ref) = @_;
    my $FHold = $$T_ref;
    while (!-s "$$C_ref\\$$T_ref") {
        unless ($$T_ref =~ s/\A[^\\]+\\(.+)\z/$1/) {
            $$T_ref = $FHold;
            last;
        }
    }
    return 1;
}
[download]

Update: I changed the .+? to [^\\]+ to be more self documenting as that is what I'm actually expecting but was relying on the greediness on .+ and laziness on .+? to get what I wanted, so this makes it easier to read.