# aria2 — Multi-Connection Downloads from the Command Line > Practical guide to aria2c — HTTP/HTTPS/FTP/BitTorrent downloads with multiple simultaneous connections, resume support and a JSON-RPC daemon. Source: https://www.jpkc.com/db/en/cheatsheets/networking/aria2/ aria2 is a lightweight, multi-protocol download utility built for speed: the `-x` and `-s` flags split a single file into segments and fetch them over multiple connections simultaneously – making it significantly faster than single-connection tools. It handles HTTP/HTTPS, FTP, BitTorrent and Metalink in one command, resumes interrupted downloads seamlessly, and exposes a JSON-RPC interface so you can queue and control downloads remotely from frontends or scripts. ## Basic Downloads `aria2c ` — Download a file from a URL. ```bash aria2c https://example.com/file.tar.gz ``` `aria2c -o ` — Download and save with a custom filename. ```bash aria2c -o backup.tar.gz https://example.com/archive-v2.tar.gz ``` `aria2c -d ` — Download to a specific directory. ```bash aria2c -d ~/Downloads https://example.com/file.zip ``` `aria2c -c ` — Resume a partially downloaded file. ```bash aria2c -c https://example.com/large-file.iso ``` `aria2c -i ` — Download URLs listed in a text file (one per line). ```bash aria2c -i urls.txt ``` ## Multi-Connection & Speed `aria2c -x ` — Use multiple connections per server (max per host). ```bash aria2c -x 8 https://example.com/large-file.iso ``` `aria2c -s ` — Split download into N pieces across connections. ```bash aria2c -s 16 https://example.com/large-file.iso ``` `aria2c -j -i ` — Download N files in parallel from a URL list. ```bash aria2c -j 5 -i urls.txt ``` `aria2c --max-download-limit= ` — Limit download speed (e.g., 500K, 2M). ```bash aria2c --max-download-limit=1M https://example.com/file.iso ``` `aria2c --max-overall-download-limit= -i ` — Limit total download speed across all downloads. ```bash aria2c --max-overall-download-limit=5M -i urls.txt ``` `aria2c --min-split-size= ` — Set minimum size for each split piece. ```bash aria2c -x 8 --min-split-size=10M https://example.com/file.iso ``` ## Multiple Sources & Mirrors `aria2c ` — Download same file from multiple mirrors simultaneously. ```bash aria2c https://mirror1.example.com/file.iso https://mirror2.example.com/file.iso ``` `aria2c -M ` — Download using a Metalink file (multiple mirrors + checksums). ```bash aria2c -M download.metalink ``` `aria2c --checksum=sha-256= ` — Verify download integrity with a checksum. ```bash aria2c --checksum=sha-256=abc123... https://example.com/file.iso ``` ## BitTorrent `aria2c ` — Download from a torrent file. ```bash aria2c ubuntu-24.04-desktop-amd64.iso.torrent ``` `aria2c ''` — Download using a magnet link. ```bash aria2c 'magnet:?xt=urn:btih:abc123...' ``` `aria2c --seed-time=0 ` — Download and exit immediately without seeding. ```bash aria2c --seed-time=0 file.torrent ``` `aria2c --select-file= ` — Download only specific files from a torrent. ```bash aria2c --select-file=1,3,5 file.torrent ``` `aria2c -S ` — Show files in a torrent without downloading. ```bash aria2c -S file.torrent ``` ## Authentication & Headers `aria2c --http-user= --http-passwd= ` — Download with HTTP Basic Authentication. ```bash aria2c --http-user=admin --http-passwd=secret https://private.example.com/file.zip ``` `aria2c --header='
' ` — Add a custom HTTP header. ```bash aria2c --header='Authorization: Bearer token123' https://api.example.com/export ``` `aria2c --ftp-user= --ftp-passwd= ` — Download from FTP with credentials. ```bash aria2c --ftp-user=admin --ftp-passwd=secret ftp://ftp.example.com/backup.tar.gz ``` `aria2c --all-proxy= ` — Use a proxy for downloads. ```bash aria2c --all-proxy=http://proxy:8080 https://example.com/file.zip ``` ## RPC & Daemon Mode `aria2c --enable-rpc` — Start aria2 as a daemon with JSON-RPC interface. ```bash aria2c --enable-rpc --rpc-listen-all=true --daemon ``` `aria2c --enable-rpc --rpc-secret=` — Start RPC daemon with authentication token. ```bash aria2c --enable-rpc --rpc-secret=mysecret --daemon ``` `aria2c --conf-path=` — Use a custom configuration file. ```bash aria2c --conf-path=~/.config/aria2/aria2.conf ``` `aria2c --save-session= --save-session-interval=60` — Save download session for later resume. ```bash aria2c --save-session=session.txt --save-session-interval=60 -i urls.txt ``` `aria2c --input-file=` — Restore downloads from a saved session. ```bash aria2c --input-file=session.txt ``` ## Conclusion aria2 shines on large files and congested links: multiple connections and mirror support squeeze every bit of available bandwidth. For recurring download tasks, pair an `aria2.conf` with the RPC daemon – this lets you manage queues from frontends like Aria2 Web UI or browser extensions without opening a new terminal each time. ## Further Reading - [aria2 – official documentation](https://aria2.github.io/) – manual and RPC reference - [aria2c(1) – manual page](https://aria2.github.io/manual/en/html/aria2c.1.html) – every option at a glance - [aria2 – Wikipedia](https://en.wikipedia.org/wiki/Aria2) – background and history ## Related Commands - [wget](https://www.jpkc.com/db/en/cheatsheets/networking/wget/) – download files and directory trees from servers - [curl](https://www.jpkc.com/db/en/cheatsheets/networking/curl/) – HTTP requests, APIs and downloads on the command line - [scp](https://www.jpkc.com/db/en/cheatsheets/networking/scp/) – transfer files securely over SSH