#!/usr/bin/perl

use strict;
use warnings;

my $PATH = 'http://a.com/a/b/c/d/e.json?something' . '/' . '/../../../';
$PATH =~ tr|/||s;
my $PREV = 0;
my $LEN;
for (;;)
{
  $PATH =~ s/\/[^\/]+\/\.\.//;
  $LEN = length($PATH);
  last if ($PREV == $LEN);
  $PREV = $LEN;
}
print $PATH;