aria2: Fast, Resumable Downloads with Parallel Connections

If you regularly download large files, especially on an unreliable internet connection, aria2 is a command-line download manager worth knowing about. It can resume broken downloads and use multiple parallel connections to speed things up, even on fast, stable connections.

Basic Usage

The simplest invocation is just aria2c followed by a URL:

aria2c 'https://example.com/large-file.zip'

Parallel Connections

The flag used most often is -x, which sets the number of parallel connections. For example, -x10 tells aria2 to open 10 simultaneous connections to the server:

aria2c -x10 'https://example.com/large-file.zip'

This can significantly speed up downloads even on fast connections, because you are pulling data through multiple streams at once instead of relying on a single connection.

Resumable Downloads

If your connection drops mid-download, aria2 picks up where it left off. You do not need to restart from scratch. This is the main reason to use it over basic tools like curl or wget for large files.

Beyond HTTP

aria2 is not limited to HTTP downloads. It also supports BitTorrent, which makes it a versatile tool for any kind of file transfer. You can use it as a single tool for direct downloads and torrent downloads alike.

Key Takeaways

• aria2c <url> downloads files with automatic resume support for broken connections.
• -x10 opens 10 parallel connections for faster downloads.
• aria2 also supports BitTorrent, making it a general-purpose download tool.

Resources

• aria2 (GitHub) -- Lightweight multi-protocol download utility with parallel connection support