>perl -e '
    sub string_to_struct {
 my $string = shift;
 
 my @refs = split /__/, $string;
 $string = "\$$refs[0]";
 for (1 .. $#refs) { $string .= "-> {q/$refs[$_]/}" };
 
 return eval "\\$string";  
}
print string_to_struct "foo__`rm xxx`"; 
'
SCALAR(0x8056ba4)

>ls
...
xxx
... 
>perl -e '
    sub string_to_struct {
 my $string = shift;
 
 my @refs = split /__/, $string;
 $string = "\$$refs[0]";
 for (1 .. $#refs) { $string .= "-> {$refs[$_]}" };
 
 return eval "\\$string";  
}
print string_to_struct "foo__`rm xxx`"; 
'

SCALAR(0x8056bb0)
> ls
[argh! xxx has been removed]