AXEL for Windows

About

Axel is a lightweight CLI download accelerator. While its more powerful alternative, aria2, offers a wider range of features, Axel is significantly easier to use when the goal is just download acceleration. However, Axel is originally written using POSIX APIs, which makes it incompatible with Windows. This repository provides a version of Axel that works on Windows.

Porting POSIX-based code to Windows typically involves removing all POSIX dependencies (e.g., arpa/inet.h) and rewriting them using Windows-native APIs. However, since Axel relies heavily on POSIX for its functionality, this would essentially require a complete rewrite. Instead, we use MSYS2 to allow minimal code modifications while enabling Axel to run on Windows.

---

Using Pre-built Release

You may simply use pre-built releases provided in this repository. However, you should still follow this to use this on native Windows environment with SSL verification support.

---

Building Axel on MSYS2

1. Install MSYS2
   If you haven’t already, install MSYS2 from https://www.msys2.org.

2. Open MSYS shell
   You must run the MSYS environment, not UCRT or MINGW shells, because only the MSYS environment supports the necessary POSIX APIs.

3. Install required packages
   Run the following command in the MSYS shell:

   pacman -S gcc autotools autoconf-archive gettext-devel pkg-config openssl-devel

4. Clone this repository

   git clone https://github.com/uklee/axel-for-windows.git
   cd axel-for-windows

5. Build Axel

   autoreconf -i
   ./configure
   make

6. The axel.exe binary should now be available for use.

---

Using Axel on Native Windows (Outside MSYS)

Although you can use the built axel.exe inside the MSYS environment, with a few additional steps you can run it directly from native Windows.

1. Create a folder and copy the following files into it:

   axel.exe
   msys64/usr/bin/msys-2.0.dll
   msys64/usr/bin/msys-crypto-3.dll
   msys64/usr/bin/msys-ssl-3.dll
   

2. Obtain an SSL certificate file
   To enable OpenSSL's certificate verification, copy cert.pem from:

   msys64/usr/ssl/cert.pem, or

   download from https://curl.se/docs/caextract.html.

3. Set the environment variable
   Add the following to your Windows environment variables:

   SSL_CERT_FILE=<path-to-cert.pem>
   

4. Run Axel
   You can now run axel.exe from that folder or add the folder to your %PATH% to use it system-wide.