---
obj: application
website: https://aria2.github.io/
repo: https://github.com/aria2/aria2
---
# aria2
[aria2](https://aria2.github.io/) is a utility for downloading files. The supported protocols are [HTTP](../../../internet/HTTP.md)(S), [FTP](../../../internet/FTP.md), SFTP, [BitTorrent](../../../internet/BitTorrent.md), and Metalink. aria2 can download a file from multiple sources/protocols and tries to utilize your maximum download bandwidth. It supports downloading a file from [HTTP](../../../internet/HTTP.md)(S)/[FTP](../../../internet/FTP.md)/SFTP and [BitTorrent](../../../internet/BitTorrent.md) at the same time, while the data downloaded from [HTTP](../../../internet/HTTP.md)(S)/[FTP](../../../internet/FTP.md)/SFTP is uploaded to the [BitTorrent](../../../internet/BitTorrent.md) swarm. Using Metalink's chunk checksums, aria2 automatically validates chunks of data while downloading a file like [BitTorrent](../../../internet/BitTorrent.md). Aria2 can be used as a downloader by [yt-dlp](../../media/yt-dlp.md).
## Usage
```shell
aria2c [<OPTIONS>] [<URI>|<MAGNET>|<TORRENT_FILE>|<METALINK_FILE>]
```
### Options
| Option | Description |
| -------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `-d, --dir=<DIR>` | The directory to store the downloaded file. |
| `-i, --input-file=<FILE>` | Downloads the URIs listed in **FILE**. |
| `-l, --log=<LOG>` | The file name of the [log file](../../../dev/Log.md). If - is specified, log is written to stdout. If empty string("") is specified, or this option is omitted, no log is written to disk at all. |
| `-j, --max-concurrent-downloads=<N>` | Set the maximum number of parallel downloads for every queue item. |
| `-V, --check-integrity [true/false]` | Check file integrity by validating piece hashes or a hash of entire file. This option has effect only in [BitTorrent](../../../internet/BitTorrent.md), Metalink downloads with checksums or [HTTP](../../../internet/HTTP.md)(S)/[FTP](../../../internet/FTP.md) downloads with --checksum option. If piece hashes are provided, this option can detect damaged portions of a file and re-download them. If a hash of entire file is provided, hash check is only done when file has been already download. This is determined by file length. If hash check fails, file is re-downloaded from scratch. If both piece hashes and a hash of entire file are provided, only piece hashes are used. Default: false |
| `-c, --continue [true/false]` | Continue downloading a partially downloaded file. Use this option to resume a download started by a web browser or another program which downloads files sequentially from the beginning. Currently this option is only applicable to [HTTP](../../../internet/HTTP.md)(S)/[FTP](../../../internet/FTP.md) downloads. |
| `--checksum=<TYPE>=<DIGEST>` | Set checksum. TYPE is hash type. The supported hash type is listed in Hash Algorithms in aria2c -v. DIGEST is hex digest. For example, setting sha-1 digest looks like this: `sha-1=0192ba11326fe2298c8cb4de616f4d4140213838` This option applies only to [HTTP](../../../internet/HTTP.md)(S)/[FTP](../../../internet/FTP.md) downloads. |
| `-x, --max-connection-per-server=<NUM>` | The maximum number of connections to one server for each download. Default: **1** |
| `-k, --min-split-size=<SIZE>` | aria2 does not split less than 2\*SIZE byte range. For example, let's consider downloading 20MiB file. If SIZE is 10M, aria2 can split file into 2 range (0-10MiB) and (10MiB-20MiB) and download it using 2 sources(if --split >= 2, of course). If SIZE is 15M, since 2\*15M > 20MiB, aria2 does not split file and download it using 1 source. You can append K or M (1K = 1024, 1M = 1024K). Possible Values: 1M -1024M Default: 20M |
| `-o, --out=<FILE>` | The file name of the downloaded file. It is always relative to the directory given in `--dir` option. |
| `-s, --split=<N>` | Download a file using N connections. If more than N URIs are given, first N URIs are used and remaining URIs are used for backup. If less than N URIs are given, those URIs are used more than once so that N connections total are made simultaneously. The number of connections to the same host is restricted by the `--max-connection-per-server` option. See also the `--min-split-size` option. Default: 5 |
| `-t, --timeout=<SEC>` | Set timeout in seconds. Default: 60 |
| `--check-certificate [true/false]` | Verify the peer using certificates specified in `--ca-certificate` option. Default: true |
| `--http-user=<USER>, --http-passwd=<PASSWD>` | Credentials for [HTTP](../../../internet/HTTP.md) Auth |
| `--header=<HEADER>` | Append HEADER to [HTTP](../../../internet/HTTP.md) request header. You can use this option repeatedly to specify more than one header:<br>`aria2c --header="X-A: b78" --header="X-B: 9J1" "http://host/file"` |
| `--load-cookies=<FILE>` | Load Cookies from FILE using the Firefox3 format (SQLite3), Chromium/Google Chrome (SQLite3) and the Mozilla/[Firefox](../../network/browsers/Firefox.md)(1.x/2.x)/Netscape format. |
| `--save-cookies=<FILE>` | Save Cookies to FILE in Mozilla/[Firefox](../../network/browsers/Firefox.md)(1.x/2.x)/ Netscape format. If FILE already exists, it is overwritten. Session Cookies are also saved and their expiry values are treated as 0. |
| `-U, --user-agent=<USER_AGENT>` | Set user agent for [HTTP](../../../internet/HTTP.md)(S) downloads. Default: `aria2/$VERSION`, $VERSION is replaced by package version. |
| `-S, --show-files [true/false]` | Print file listing of ".torrent", ".meta4" and ".metalink" file and exit. In case of ".torrent" file, additional information (infohash, piece length, etc) is also printed. |
| `--select-file=<INDEX>...` | (Torrent) Set file to download by specifying its index. You can find the file index using the `--show-files` option. Multiple indexes can be specified by using `,`, for example: `3,6`. You can also use `-` to specify a range: `1-5`. `,` and `-` can be used together: `1-5,8,9`. |