mulk is described as 'Multi-connection command line tool to download Internet sites. Similar to wget and cURL, but it manages up to 50 parallel links. Main features are: recursive fetching, Metalink retrieving, segmented download and image filtering by width and height' and is an app in the OS & Utilities category. There are three alternatives to mulk for a variety of platforms, including Linux, Mac, Windows, Xfce and Android. The best alternative is Wget, which is both free and Open Source. Other great apps like mulk are aria2 (Free, Open Source) and aget (Free, Open Source).
GNU Wget is a free software package for retrieving files using HTTP(S) and FTP, the most widely-used Internet protocols. It is a non-interactive command line tool, so it may easily be called from scripts, cron jobs, terminals without X-Windows support, etc.
Aget is a multithreaded HTTP -for now- download accelerator. Everybody knows about the famous Flashget for Win32. This program is a starting point of a very useful project like Flashget. The aim is to provide as much functionality as we can.