aria2c(1)

aria2c(1)

SYNOPSIS

aria2c [<OPTIONS>] [<URI>|<MAGNET>|<TORRENT_FILE>|<METALINK_FILE>] ...

DESCRIPTION

aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, SFTP, BitTorrent, 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(S)/FTP /SFTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP/SFTP is uploaded to the BitTorrent swarm. Using Metalink chunk checksums, aria2 automatically validates chunks of data while downloading a file.

OPTIONS

Note

Most FTP related options are applicable to SFTP as well. Some options are not effective against SFTP (e.g., --ftp-pasv)

Basic Options

-d, --dir=<DIR> : The directory to store the downloaded file.

-i, --input-file=<FILE> : Downloads the URIs listed in FILE. You can specify multiple sources for a single entity by putting multiple URIs on a single line separated by the TAB character. Additionally, options can be specified after each URI line. Option lines must start with one or more white space characters (SPACE or TAB) and must only contain one option per line. Input files can use gzip compression. When FILE is specified as -, aria2 will read the input from stdin. See the Input File subsection for details. See also the --deferred-input option. See also the --save-session option.

-l, --log=<LOG> : The file name of the log file. 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. See also the --split option. Default: 5

#### Note

[`--max-concurrent-downloads`](#cmdoption-j) limits the number of items
which are downloaded concurrently. [`--split`](#cmdoption-s) and
[`--min-split-size`](#cmdoption-k) affect the number of connections
inside each item. Imagine that you have an input file (see
[`--input-file`](#cmdoption-i) option) like this:

```
http://example.com/foo
http://example.com/bar
```

Here is 2 download items. aria2 can download these items
concurrently if the value more than or equal 2 is given to
[`--max-concurrent-downloads`](#cmdoption-j). In each download item, you
can configure the number of connections using [`--split`](#cmdoption-s) and/or [`--min-split-size`](#cmdoption-k), etc.

-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, Metalink downloads with checksums or HTTP(S)/FTP 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(S)/FTP downloads.

-h, --help[=<TAG>|<KEYWORD>] : The help messages are classified with tags. A tag starts with #. For example, type --help=#http to get the usage for the options tagged with #http. If non-tag word is given, print the usage for the options whose name includes that word. Available Values: #basic, #advanced, #http, #https, #ftp, #metalink, #bittorrent, #cookie, #hook, #file, #rpc, #checksum, #experimental, #deprecated, #help, #all Default: #basic

HTTP/FTP/SFTP Options

--all-proxy=<PROXY> : Use a proxy server for all protocols. To override a previously defined proxy, use “”. You also can override this setting and specify a proxy server for a particular protocol using --http-proxy, --https-proxy and --ftp-proxy options. This affects all downloads. The format of PROXY is [http://][USER:PASSWORD@]HOST[:PORT]. See also ENVIRONMENT section.

#### Note

If user and password are embedded in proxy URI and they are also
specified by *--{http,https,ftp,all}-proxy-{user,passwd}* options,
those specified later override prior options. For example, if you specified
`http-proxy-user=myname`, `http-proxy-passwd=mypass` in aria2.conf and
you specified `--http-proxy=“http://proxy”` on the command-line, then
you'd get HTTP proxy `http://proxy` with user `myname` and password
`mypass`.

Another example: if you specified on the command-line
`--http-proxy=“http://user:pass@proxy” --http-proxy-user=“myname”
--http-proxy-passwd=“mypass”`, then you'd get HTTP proxy
`http://proxy` with user `myname` and password `mypass`.

One more example: if you specified in command-line `--http-proxy-user=“myname”
--http-proxy-passwd=“mypass” --http-proxy=“http://user:pass@proxy”`,
then you'd get HTTP proxy `http://proxy` with user `user` and password
`pass`.

--all-proxy-passwd=<PASSWD> : Set password for --all-proxy option.

--all-proxy-user=<USER> : Set user for --all-proxy option.

--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(S)/FTP downloads.

--connect-timeout=<SEC> : Set the connect timeout in seconds to establish connection to HTTP/FTP/proxy server. After the connection is established, this option makes no effect and --timeout option is used instead. Default: 60

--dry-run [true|false] : If true is given, aria2 just checks whether the remote file is available and doesn't download data. This option has effect on HTTP/FTP download. BitTorrent downloads are canceled if true is specified. Default: false

--lowest-speed-limit=<SPEED> : Close connection if download speed is lower than or equal to this value(bytes per sec). 0 means aria2 does not have a lowest speed limit. You can append K or M (1K = 1024, 1M = 1024K). This option does not affect BitTorrent downloads. Default: 0

-x, --max-connection-per-server=<NUM> : The maximum number of connections to one server for each download. Default: 1

--max-file-not-found=<NUM> : If aria2 receives “file not found” status from the remote HTTP/FTP servers NUM times without getting a single byte, then force the download to fail. Specify 0 to disable this option. This options is effective only when using HTTP/FTP servers. The number of retry attempt is counted toward --max-tries, so it should be configured too.

Default: `0`

-m, --max-tries=<N> : Set number of tries. 0 means unlimited. See also --retry-wait. Default: 5

-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

--netrc-path=<FILE> : Specify the path to the netrc file. Default: $(HOME)/.netrc

#### Note

Permission of the .netrc file must be 600. Otherwise, the file
will be ignored.

-n, --no-netrc [true|false] : Disables netrc support. netrc support is enabled by default.

#### Note

netrc file is only read at the startup if
[`--no-netrc`](#cmdoption-n) is `false`.
So if [`--no-netrc`](#cmdoption-n) is `true` at the startup,
no netrc is available throughout the session.
You cannot get netrc enabled even if you send
[`--no-netrc=false`](#cmdoption-n) using
[`aria2.changeGlobalOption()`](#aria2.changeGlobalOption).

--no-proxy=<DOMAINS> : Specify a comma separated list of host names, domains and network addresses with or without a subnet mask where no proxy should be used.

#### Note

For network addresses with a subnet mask, both IPv4 and IPv6 addresses work.
The current implementation does not resolve the host name in an URI to compare
network addresses specified in [`--no-proxy`](#cmdoption-no-proxy). So it is only effective
if URI has numeric IP addresses.

-o, --out=<FILE> : The file name of the downloaded file. It is always relative to the directory given in --dir option. When the --force-sequential option is used, this option is ignored.

#### Note

You cannot specify a file name for Metalink or BitTorrent downloads.
The file name specified here is only used when the URIs fed to aria2
are given on the command line directly, but not when using
[`--input-file`](#cmdoption-i), [`--force-sequential`](#cmdoption-Z) option.

Example:

```
$ aria2c -o myfile.zip "http://mirror1/file.zip" "http://mirror2/file.zip"
```

--proxy-method=<METHOD> : Set the method to use in proxy request. METHOD is either get or tunnel. HTTPS downloads always use tunnel regardless of this option. Default: get

-R, --remote-time [true|false] : Retrieve timestamp of the remote file from the remote HTTP/FTP server and if it is available, apply it to the local file. Default: false

--reuse-uri [true|false] : Reuse already used URIs if no unused URIs are left. Default: true

--retry-wait=<SEC> : Set the seconds to wait between retries. When SEC > 0, aria2 will retry downloads when the HTTP server returns a 503 response. Default: 0

--server-stat-of=<FILE> : Specify the file name to which performance profile of the servers is saved. You can load saved data using --server-stat-if option. See Server Performance Profile subsection below for file format.

--server-stat-if=<FILE> : Specify the file name to load performance profile of the servers. The loaded data will be used in some URI selector such as feedback. See also --uri-selector option. See Server Performance Profile subsection below for file format.

--server-stat-timeout=<SEC> : Specifies timeout in seconds to invalidate performance profile of the servers since the last contact to them. Default: 86400 (24hours)

-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

#### Note

Some Metalinks regulate the number of servers to connect. aria2
strictly respects them. This means that if Metalink defines the
`maxconnections` attribute lower than N, then aria2 uses the
value of this lower value instead of N.

--stream-piece-selector=<SELECTOR> : Specify piece selection algorithm used in HTTP/FTP download. A piece is a fixed length segment which is downloaded in parallel in a segmented download. Default: default.

default
:   Select a piece to reduce the number of connections established.
    This is reasonable default behavior because establishing a connection is an
    expensive operation.

inorder
:   Select a piece closest to the beginning of the file. This is useful for
    viewing movies while downloading. [`--enable-http-pipelining`](#cmdoption-enable-http-pipelining) option
    may be useful to reduce re-connection overhead. Note that aria2 honors
    [`--min-split-size`](#cmdoption-k) option, so it will be necessary to specify
    a reasonable value to [`--min-split-size`](#cmdoption-k) option.

random
:   Select a piece randomly. Like `inorder`, [`--min-split-size`](#cmdoption-k)
    option is honored.

geom
:   When starting to download a file, select a piece closest to the beginning
    of the file like `inorder`, but then exponentially increases space
    between pieces.
    This reduces the number of connections established, while
    at the same time downloads the beginning part of the file first. This is
    useful for viewing movies while downloading.

-t, --timeout=<SEC> : Set timeout in seconds. Default: 60

--uri-selector=<SELECTOR> : Specify URI selection algorithm. The possible values are inorder, feedback and adaptive. If inorder is given, URI is tried in the order appeared in the URI list. If feedback is given, aria2 uses download speed observed in the previous downloads and choose fastest server in the URI list. This also effectively skips dead mirrors. The observed download speed is a part of performance profile of servers mentioned in --server-stat-of and --server-stat-if options. If adaptive is given, selects one of the best mirrors for the first and reserved connections. For supplementary ones, it returns mirrors which has not been tested yet, and if each of them has already been tested, returns mirrors which has to be tested again. Otherwise, it doesn't select anymore mirrors. Like feedback, it uses a performance profile of servers. Default: feedback

HTTP Specific Options

--ca-certificate=<FILE> : Use the certificate authorities in FILE to verify the peers. The certificate file must be in PEM format and can contain multiple CA certificates. Use --check-certificate option to enable verification.

#### Note

If you build with OpenSSL or the recent version of GnuTLS which
has `gnutls_certificate_set_x509_system_trust()` function and
the library is properly configured to locate the system-wide CA
certificates store, aria2 will automatically load those
certificates at the startup.

#### Note

*WinTLS* and *AppleTLS* do not support this option. Instead you will
have to import the certificate into the OS trust store.

--certificate=<FILE> : Use the client certificate in FILE. The certificate must be either in PKCS12 (.p12, .pfx) or in PEM format.

PKCS12 files must contain the certificate, a key and optionally a chain
of additional certificates. Only PKCS12 files with a blank import password
can be opened!

When using PEM, you have to specify the private key via [`--private-key`](#cmdoption-private-key)
as well.

#### Note

*WinTLS* does not support PEM files at the moment. Users have to use PKCS12
files.

#### Note

*AppleTLS* users should use the KeyChain Access utility to import the client
certificate and get the SHA-1 fingerprint from the Information dialog
corresponding to that certificate.
To start aria2c use --certificate=&lt;SHA-1>.
Alternatively PKCS12 files are also supported. PEM files, however, are not
supported.

--check-certificate [true|false] : Verify the peer using certificates specified in --ca-certificate option. Default: true

--http-accept-gzip [true|false] : Send Accept-Encoding: deflate, gzip request header and inflate response if remote server responds with Content-Encoding: gzip or Content-Encoding: deflate. Default: false

#### Note

Some server responds with `Content-Encoding: gzip` for files which
itself is gzipped file. aria2 inflates them anyway because of the
response header.

--http-auth-challenge [true|false] : Send HTTP authorization header only when it is requested by the server. If false is set, then authorization header is always sent to the server. There is an exception: if user name and password are embedded in URI, authorization header is always sent to the server regardless of this option. Default: false

--http-no-cache [true|false] : Send Cache-Control: no-cache and Pragma: no-cache header to avoid cached content. If false is given, these headers are not sent and you can add Cache-Control header with a directive you like using --header option. Default: false

--http-user=<USER> : Set HTTP user. This affects all URIs.

--http-passwd=<PASSWD> : Set HTTP password. This affects all URIs.

--http-proxy=<PROXY> : Use a proxy server for HTTP. To override a previously defined proxy, use “”. See also the --all-proxy option. This affects all http downloads. The format of PROXY is [http://][USER:PASSWORD@]HOST[:PORT]

--http-proxy-passwd=<PASSWD> : Set password for --http-proxy.

--http-proxy-user=<USER> : Set user for --http-proxy.

--https-proxy=<PROXY> : Use a proxy server for HTTPS. To override a previously defined proxy, use “”. See also the --all-proxy option. This affects all https download. The format of PROXY is [http://][USER:PASSWORD@]HOST[:PORT]

--https-proxy-passwd=<PASSWD> : Set password for --https-proxy.

--https-proxy-user=<USER> : Set user for --https-proxy.

--private-key=<FILE> : Use the private key in FILE. The private key must be decrypted and in PEM format. An encrypted key may cause undefined behavior. See also --certificate option.

--referer=<REFERER> : Set an http referrer (Referer). This affects all http/https downloads. If * is given, the download URI is also used as the referrer. This may be useful when used together with the --parameterized-uri option.

--enable-http-keep-alive [true|false] : Enable HTTP/1.1 persistent connection. Default: true

--enable-http-pipelining [true|false] : Enable HTTP/1.1 pipelining. Default: false

#### Note

There is usually no performance gain from enabling this option.

: Append HEADER to HTTP request header. You can use this option repeatedly to specify more than one header:

```
$ 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(1.x/2.x)/Netscape format.

#### Note

If aria2 is built without libsqlite3, then it doesn't support Firefox3
and Chromium/Google Chrome cookie format.

--save-cookies=<FILE> : Save Cookies to FILE in Mozilla/Firefox(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. Possible Values: /path/to/file

--use-head [true|false] : Use HEAD method for the first request to the HTTP server. Default: false

: Whether to disable Want-Digest header when doing requests. Default: false

-U, --user-agent=<USER_AGENT> : Set user agent for HTTP(S) downloads. Default: aria2/$VERSION, $VERSION is replaced by package version.

FTP/SFTP Specific Options

--ftp-user=<USER> : Set FTP user. This affects all URIs. Default: anonymous

--ftp-passwd=<PASSWD> : Set FTP password. This affects all URIs. If user name is embedded but password is missing in URI, aria2 tries to resolve password using .netrc. If password is found in .netrc, then use it as password. If not, use the password specified in this option. Default: ARIA2USER@

-p, --ftp-pasv [true|false] : Use the passive mode in FTP. If false is given, the active mode will be used. Default: true

#### Note

This option is ignored for SFTP transfer.

--ftp-proxy=<PROXY> : Use a proxy server for FTP. To override a previously defined proxy, use “”. See also the --all-proxy option. This affects all ftp downloads. The format of PROXY is [http://][USER:PASSWORD@]HOST[:PORT]

--ftp-proxy-passwd=<PASSWD> : Set password for --ftp-proxy option.

--ftp-proxy-user=<USER> : Set user for --ftp-proxy option.

--ftp-type=<TYPE> : Set FTP transfer type. TYPE is either binary or ascii. Default: binary

#### Note

This option is ignored for SFTP transfer.

--ftp-reuse-connection [true|false] : Reuse connection in FTP. Default: true

--ssh-host-key-md=<TYPE>=<DIGEST> : Set checksum for SSH host public key. TYPE is hash type. The supported hash type is sha-1 or md5. DIGEST is hex digest. For example: sha-1=b030503d4de4539dc7885e6f0f5e256704edf4c3. This option can be used to validate server's public key when SFTP is used. If this option is not set, which is default, no validation takes place.

BitTorrent/Metalink Options

--select-file=<INDEX>... : 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. When used with the -M option, index may vary depending on the query (see --metalink-* options).

#### Note

In multi file torrent, the adjacent files specified by this option may
also be downloaded. This is by design, not a bug.
A single piece may include several files or part of files, and aria2
writes the piece to the appropriate files.

-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.

BitTorrent Specific Options

--bt-detach-seed-only [true|false] : Exclude seed only downloads when counting concurrent active downloads (See -j option). This means that if -j3 is given and this option is turned on and 3 downloads are active and one of those enters seed mode, then it is excluded from active download count (thus it becomes 2), and the next download waiting in queue gets started. But be aware that seeding item is still recognized as active download in RPC method. Default: false

--bt-enable-hook-after-hash-check [true|false] : Allow hook command invocation after hash check (see -V option) in BitTorrent download. By default, when hash check succeeds, the command given by --on-bt-download-complete is executed. To disable this action, give false to this option. Default: true

--bt-enable-lpd [true|false] : Enable Local Peer Discovery. If a private flag is set in a torrent, aria2 doesn't use this feature for that download even if true is given. Default: false

--bt-exclude-tracker=<URI>[,...] : Comma separated list of BitTorrent tracker's announce URI to remove. You can use special value * which matches all URIs, thus removes all announce URIs. When specifying * in shell command-line, don't forget to escape or quote it. See also --bt-tracker option.

--bt-external-ip=<IPADDRESS> : Specify the external IP address to use in BitTorrent download and DHT. It may be sent to BitTorrent tracker. For DHT, this option should be set to report that local node is downloading a particular torrent. This is critical to use DHT in a private network. Although this function is named external, it can accept any kind of IP addresses.

--bt-force-encryption [true|false] : Requires BitTorrent message payload encryption with arc4. This is a shorthand of --bt-require-crypto --bt-min-crypto-level=arc4. This option does not change the option value of those options. If true is given, deny legacy BitTorrent handshake and only use Obfuscation handshake and always encrypt message payload. Default: false

--bt-hash-check-seed [true|false] : If true is given, after hash check using --check-integrity option and file is complete, continue to seed file. If you want to check file and download it only when it is damaged or incomplete, set this option to false. This option has effect only on BitTorrent download. Default: true

--bt-load-saved-metadata [true|false] : Before getting torrent metadata from DHT when downloading with magnet link, first try to read file saved by --bt-save-metadata option. If it is successful, then skip downloading metadata from DHT. Default: false

--bt-lpd-interface=<INTERFACE> : Use given interface for Local Peer Discovery. If this option is not specified, the default interface is chosen. You can specify interface name and IP address. Possible Values: interface, IP address

--bt-max-open-files=<NUM> : Specify maximum number of files to open in multi-file BitTorrent/Metalink download globally. Default: 100

--bt-max-peers=<NUM> : Specify the maximum number of peers per torrent. 0 means unlimited. See also --bt-request-peer-speed-limit option. Default: 55

--bt-metadata-only [true|false] : Download metadata only. The file(s) described in metadata will not be downloaded. This option has effect only when BitTorrent Magnet URI is used. See also --bt-save-metadata option. Default: false

--bt-min-crypto-level=plain|arc4 : Set minimum level of encryption method. If several encryption methods are provided by a peer, aria2 chooses the lowest one which satisfies the given level. Default: plain

--bt-prioritize-piece=head[=<SIZE>],tail[=<SIZE>] : Try to download first and last pieces of each file first. This is useful for previewing files. The argument can contain 2 keywords: head and tail. To include both keywords, they must be separated by comma. These keywords can take one parameter, SIZE. For example, if head=<SIZE> is specified, pieces in the range of first SIZE bytes of each file get higher priority. tail=<SIZE> means the range of last SIZE bytes of each file. SIZE can include K or M (1K = 1024, 1M = 1024K). If SIZE is omitted, SIZE=1M is used.

--bt-remove-unselected-file [true|false] : Removes the unselected files when download is completed in BitTorrent. To select files, use --select-file option. If it is not used, all files are assumed to be selected. Please use this option with care because it will actually remove files from your disk. Default: false

--bt-require-crypto [true|false] : If true is given, aria2 doesn't accept and establish connection with legacy BitTorrent handshake(\19BitTorrent protocol). Thus aria2 always uses Obfuscation handshake. Default: false

--bt-request-peer-speed-limit=<SPEED> : If the whole download speed of every torrent is lower than SPEED, aria2 temporarily increases the number of peers to try for more download speed. Configuring this option with your preferred download speed can increase your download speed in some cases. You can append K or M (1K = 1024, 1M = 1024K). Default: 50K

--bt-save-metadata [true|false] : Save metadata as “.torrent” file. This option has effect only when BitTorrent Magnet URI is used. The file name is hex encoded info hash with suffix “.torrent”. The directory to be saved is the same directory where download file is saved. If the same file already exists, metadata is not saved. See also --bt-metadata-only option. Default: false

--bt-seed-unverified [true|false] : Seed previously downloaded files without verifying piece hashes. Default: false

--bt-stop-timeout=<SEC> : Stop BitTorrent download if download speed is 0 in consecutive SEC seconds. If 0 is given, this feature is disabled. Default: 0

--bt-tracker=<URI>[,...] : Comma separated list of additional BitTorrent tracker's announce URI. These URIs are not affected by --bt-exclude-tracker option because they are added after URIs in --bt-exclude-tracker option are removed.

--bt-tracker-connect-timeout=<SEC> : Set the connect timeout in seconds to establish connection to tracker. After the connection is established, this option makes no effect and --bt-tracker-timeout option is used instead. Default: 60

--bt-tracker-interval=<SEC> : Set the interval in seconds between tracker requests. This completely overrides interval value and aria2 just uses this value and ignores the min interval and interval value in the response of tracker. If 0 is set, aria2 determines interval based on the response of tracker and the download progress. Default: 0

--bt-tracker-timeout=<SEC> : Set timeout in seconds. Default: 60

--dht-entry-point=<HOST>:<PORT> : Set host and port as an entry point to IPv4 DHT network.

--dht-entry-point6=<HOST>:<PORT> : Set host and port as an entry point to IPv6 DHT network.

--dht-file-path=<PATH> : Change the IPv4 DHT routing table file to PATH. Default: $HOME/.aria2/dht.dat if present, otherwise $XDG_CACHE_HOME/aria2/dht.dat.

--dht-file-path6=<PATH> : Change the IPv6 DHT routing table file to PATH. Default: $HOME/.aria2/dht6.dat if present, otherwise $XDG_CACHE_HOME/aria2/dht6.dat.

--dht-listen-addr6=<ADDR> : Specify address to bind socket for IPv6 DHT. It should be a global unicast IPv6 address of the host.

--dht-listen-port=<PORT>... : Set UDP listening port used by DHT(IPv4, IPv6) and UDP tracker. Multiple ports can be specified by using ,, for example: 6881,6885. You can also use - to specify a range: 6881-6999. , and - can be used together. Default: 6881-6999

#### Note

Make sure that the specified ports are open for incoming UDP traffic.

--dht-message-timeout=<SEC> : Set timeout in seconds. Default: 10

--enable-dht [true|false] : Enable IPv4 DHT functionality. It also enables UDP tracker support. If a private flag is set in a torrent, aria2 doesn't use DHT for that download even if true is given. Default: true

--enable-dht6 [true|false] : Enable IPv6 DHT functionality. If a private flag is set in a torrent, aria2 doesn't use DHT for that download even if true is given. Use --dht-listen-port option to specify port number to listen on. See also --dht-listen-addr6 option.

--enable-peer-exchange [true|false] : Enable Peer Exchange extension. If a private flag is set in a torrent, this feature is disabled for that download even if true is given. Default: true

--follow-torrent=true|false|mem : If true or mem is specified, when a file whose suffix is .torrent or content type is application/x-bittorrent is downloaded, aria2 parses it as a torrent file and downloads files mentioned in it. If mem is specified, a torrent file is not written to the disk, but is just kept in memory. If false is specified, the .torrent file is downloaded to the disk, but is not parsed as a torrent and its contents are not downloaded. Default: true

-O, --index-out=<INDEX>=<PATH> : Set file path for file with index=INDEX. You can find the file index using the --show-files option. PATH is a relative path to the path specified in --dir option. You can use this option multiple times. Using this option, you can specify the output file names of BitTorrent downloads.

--listen-port=<PORT>... : Set TCP port number for BitTorrent downloads. Multiple ports can be specified by using ,, for example: 6881,6885. You can also use - to specify a range: 6881-6999. , and - can be used together: 6881-6889,6999. Default: 6881-6999

#### Note

Make sure that the specified ports are open for incoming TCP traffic.

--max-overall-upload-limit=<SPEED> : Set max overall upload speed in bytes/sec. 0 means unrestricted. You can append K or M (1K = 1024, 1M = 1024K). To limit the upload speed per torrent, use --max-upload-limit option. Default: 0

-u, --max-upload-limit=<SPEED> : Set max upload speed per each torrent in bytes/sec. 0 means unrestricted. You can append K or M (1K = 1024, 1M = 1024K). To limit the overall upload speed, use --max-overall-upload-limit option. Default: 0

--peer-id-prefix=<PEER_ID_PREFIX> : Specify the prefix of peer ID. The peer ID in BitTorrent is 20 byte length. If more than 20 bytes are specified, only first 20 bytes are used. If less than 20 bytes are specified, random byte data are added to make its length 20 bytes.

Default: `A2-$MAJOR-$MINOR-$PATCH-`, $MAJOR, $MINOR and $PATCH are
replaced by major, minor and patch version number respectively. For
instance, aria2 version 1.18.8 has prefix ID `A2-1-18-8-`.

--peer-agent=<PEER_AGENT> : Specify the string used during the bitorrent extended handshake for the peer's client version.

Default: `aria2/$MAJOR.$MINOR.$PATCH`, $MAJOR, $MINOR and $PATCH are
replaced by major, minor and patch version number respectively. For
instance, aria2 version 1.18.8 has peer agent `aria2/1.18.8`.

--seed-ratio=<RATIO> : Specify share ratio. Seed completed torrents until share ratio reaches RATIO. You are strongly encouraged to specify equals or more than 1.0 here. Specify 0.0 if you intend to do seeding regardless of share ratio. If --seed-time option is specified along with this option, seeding ends when at least one of the conditions is satisfied. Default: 1.0

--seed-time=<MINUTES> : Specify seeding time in (fractional) minutes. Also see the --seed-ratio option.

#### Note

Specifying [`--seed-time=0`](#cmdoption-seed-time) disables seeding after download completed.

-T, --torrent-file=<TORRENT_FILE> : The path to the “.torrent” file. You are not required to use this option because you can specify “.torrent” files without --torrent-file.

Metalink Specific Options

--follow-metalink=true|false|mem : If true or mem is specified, when a file whose suffix is .meta4 or .metalink or content type of application/metalink4+xml or application/metalink+xml is downloaded, aria2 parses it as a metalink file and downloads files mentioned in it. If mem is specified, a metalink file is not written to the disk, but is just kept in memory. If false is specified, the .metalink file is downloaded to the disk, but is not parsed as a metalink file and its contents are not downloaded. Default: true

--metalink-base-uri=<URI> : Specify base URI to resolve relative URI in metalink:url and metalink:metaurl element in a metalink file stored in local disk. If URI points to a directory, URI must end with /.

-M, --metalink-file=<METALINK_FILE> : The file path to “.meta4” and “.metalink” file. Reads input from stdin when - is specified. You are not required to use this option because you can specify “.metalink” files without --metalink-file.

--metalink-language=<LANGUAGE> : The language of the file to download.

--metalink-location=<LOCATION>[,...] : The location of the preferred server. A comma-delimited list of locations is acceptable, for example, jp,us.

--metalink-os=<OS> : The operating system of the file to download.

--metalink-version=<VERSION> : The version of the file to download.

--metalink-preferred-protocol=<PROTO> : Specify preferred protocol. The possible values are http, https, ftp and none. Specify none to disable this feature. Default: none

--metalink-enable-unique-protocol [true|false] : If true is given and several protocols are available for a mirror in a metalink file, aria2 uses one of them. Use --metalink-preferred-protocol option to specify the preference of protocol. Default: true

RPC Options

--enable-rpc [true|false] : Enable JSON-RPC/XML-RPC server. It is strongly recommended to set secret authorization token using --rpc-secret option. See also --rpc-listen-port option. Default: false

--pause [true|false] : Pause download after added. This option is effective only when --enable-rpc=true is given. Default: false

--pause-metadata [true|false] : Pause downloads created as a result of metadata download. There are 3 types of metadata downloads in aria2: (1) downloading .torrent file. (2) downloading torrent metadata using magnet link. (3) downloading metalink file. These metadata downloads will generate downloads using their metadata. This option pauses these subsequent downloads. This option is effective only when --enable-rpc=true is given. Default: false

--rpc-allow-origin-all [true|false] : Add Access-Control-Allow-Origin header field with value * to the RPC response. Default: false

--rpc-certificate=<FILE> : Use the certificate in FILE for RPC server. The certificate must be either in PKCS12 (.p12, .pfx) or in PEM format.

PKCS12 files must contain the certificate, a key and optionally a chain
of additional certificates. Only PKCS12 files with a blank import password
can be opened!

When using PEM, you have to specify the private key via [`--rpc-private-key`](#cmdoption-rpc-private-key)
as well. Use [`--rpc-secure`](#cmdoption-rpc-secure) option to enable encryption.

#### Note

*WinTLS* does not support PEM files at the moment. Users have to use PKCS12
files.

#### Note

*AppleTLS* users should use the KeyChain Access utility to first generate a
self-signed SSL-Server certificate, e.g. using the wizard, and get the
SHA-1 fingerprint from the Information dialog corresponding to that new
certificate.
To start aria2c with [`--rpc-secure`](#cmdoption-rpc-secure) use
--rpc-certificate=&lt;SHA-1>.
Alternatively PKCS12 files are also supported. PEM files, however, are not
supported.

--rpc-listen-all [true|false] : Listen incoming JSON-RPC/XML-RPC requests on all network interfaces. If false is given, listen only on local loopback interface. Default: false

--rpc-listen-port=<PORT> : Specify a port number for JSON-RPC/XML-RPC server to listen to. Possible Values: 1024 -65535 Default: 6800

--rpc-max-request-size=<SIZE> : Set max size of JSON-RPC/XML-RPC request. If aria2 detects the request is more than SIZE bytes, it drops connection. Default: 2M

--rpc-passwd=<PASSWD> : Set JSON-RPC/XML-RPC password.

#### Warning

[`--rpc-passwd`](#cmdoption-rpc-passwd) option will be deprecated in the future
release. Migrate to [`--rpc-secret`](#cmdoption-rpc-secret) option as soon as
possible.

--rpc-private-key=<FILE> : Use the private key in FILE for RPC server. The private key must be decrypted and in PEM format. Use --rpc-secure option to enable encryption. See also --rpc-certificate option.

--rpc-save-upload-metadata [true|false] : Save the uploaded torrent or metalink metadata in the directory specified by --dir option. The file name consists of SHA-1 hash hex string of metadata plus extension. For torrent, the extension is '.torrent'. For metalink, it is '.meta4'. If false is given to this option, the downloads added by aria2.addTorrent() or aria2.addMetalink() will not be saved by --save-session option. Default: true

--rpc-secret=<TOKEN> : Set RPC secret authorization token. Read RPC authorization secret token to know how this option value is used.

--rpc-secure [true|false] : RPC transport will be encrypted by SSL/TLS. The RPC clients must use https scheme to access the server. For WebSocket client, use wss scheme. Use --rpc-certificate and --rpc-private-key options to specify the server certificate and private key.

--rpc-user=<USER> : Set JSON-RPC/XML-RPC user.

#### Warning

[`--rpc-user`](#cmdoption-rpc-user) option will be deprecated in the future
release. Migrate to [`--rpc-secret`](#cmdoption-rpc-secret) option as soon as
possible.

Advanced Options

--allow-overwrite [true|false] : Restart download from scratch if the corresponding control file doesn't exist. See also --auto-file-renaming option. Default: false

--allow-piece-length-change [true|false] : If false is given, aria2 aborts download when a piece length is different from one in a control file. If true is given, you can proceed but some download progress will be lost. Default: false

--always-resume [true|false] : Always resume download. If true is given, aria2 always tries to resume download and if resume is not possible, aborts download. If false is given, when all given URIs do not support resume or aria2 encounters N URIs which does not support resume (N is the value specified using --max-resume-failure-tries option), aria2 downloads file from scratch. See --max-resume-failure-tries option. Default: true

--async-dns [true|false] : Enable asynchronous DNS. Default: true

--async-dns-server=<IPADDRESS>[,...] : Comma separated list of DNS server address used in asynchronous DNS resolver. Usually asynchronous DNS resolver reads DNS server addresses from /etc/resolv.conf. When this option is used, it uses DNS servers specified in this option instead of ones in /etc/resolv.conf. You can specify both IPv4 and IPv6 address. This option is useful when the system does not have /etc/resolv.conf and user does not have the permission to create it.

--auto-file-renaming [true|false] : Rename file name if the same file already exists. This option works only in HTTP(S)/FTP download. The new file name has a dot and a number(1..9999) appended after the name, but before the file extension, if any. Default: true

--auto-save-interval=<SEC> : Save a control file(*.aria2) every SEC seconds. If 0 is given, a control file is not saved during download. aria2 saves a control file when it stops regardless of the value. The possible values are between 0 to 600. Default: 60

--conditional-get [true|false] : Download file only when the local file is older than remote fil

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