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GNU Wget Manual

2.5 Download Options

`--bind-address=ADDRESS'

When making client TCP/IP connections, bind() to ADDRESS on the local machine. ADDRESS may be specified as a hostname or IP address. This option can be useful if your machine is bound to multiple IPs.

`-t number'

`--tries=number'

Set number of retries to number. Specify 0 or `inf' for infinite retrying.

`-O file'

`--output-document=file'

The documents will not be written to the appropriate files, but all will be concatenated together and written to file. If file already exists, it will be overwritten. If the file is `-', the documents will be written to standard output. Including this option automatically sets the number of tries to 1.

`-nc'

`--no-clobber'

If a file is downloaded more than once in the same directory, Wget's behavior depends on a few options, including `-nc'. In certain cases, the local file will be clobbered, or overwritten, upon repeated download. In other cases it will be preserved.

When running Wget without `-N', `-nc', or `-r', downloading the same file in the same directory will result in the original copy of file being preserved and the second copy being named `file.1'. If that file is downloaded yet again, the third copy will be named `file.2', and so on. When `-nc' is specified, this behavior is suppressed, and Wget will refuse to download newer copies of `file'. Therefore, "no-clobber" is actually a misnomer in this mode--it's not clobbering that's prevented (as the numeric suffixes were already preventing clobbering), but rather the multiple version saving that's prevented.

When running Wget with `-r', but without `-N' or `-nc', re-downloading a file will result in the new copy simply overwriting the old. Adding `-nc' will prevent this behavior, instead causing the original version to be preserved and any newer copies on the server to be ignored.

When running Wget with `-N', with or without `-r', the decision as to whether or not to download a newer copy of a file depends on the local and remote timestamp and size of the file (see section 5. Time-Stamping). `-nc' may not be specified at the same time as `-N'.

Note that when `-nc' is specified, files with the suffixes `.html' or (yuck) `.htm' will be loaded from the local disk and parsed as if they had been retrieved from the Web.

`-c'

`--continue'

Continue getting a partially-downloaded file. This is useful when you want to finish up a download started by a previous instance of Wget, or by another program. For instance:

wget -c ftp://sunsite.doc.ic.ac.uk/ls-lR.Z

If there is a file named `ls-lR.Z' in the current directory, Wget will assume that it is the first portion of the remote file, and will ask the server to continue the retrieval from an offset equal to the length of the local file.

Note that you don't need to specify this option if you just want the current invocation of Wget to retry downloading a file should the connection be lost midway through. This is the default behavior. `-c' only affects resumption of downloads started prior to this invocation of Wget, and whose local files are still sitting around.

Without `-c', the previous example would just download the remote file to `ls-lR.Z.1', leaving the truncated `ls-lR.Z' file alone.

Beginning with Wget 1.7, if you use `-c' on a non-empty file, and it turns out that the server does not support continued downloading, Wget will refuse to start the download from scratch, which would effectively ruin existing contents. If you really want the download to start from scratch, remove the file.

Also beginning with Wget 1.7, if you use `-c' on a file which is of equal size as the one on the server, Wget will refuse to download the file and print an explanatory message. The same happens when the file is smaller on the server than locally (presumably because it was changed on the server since your last download attempt)---because "continuing" is not meaningful, no download occurs.

On the other side of the coin, while using `-c', any file that's bigger on the server than locally will be considered an incomplete download and only (length(remote) - length(local)) bytes will be downloaded and tacked onto the end of the local file. This behavior can be desirable in certain cases--for instance, you can use `wget -c' to download just the new portion that's been appended to a data collection or log file.

However, if the file is bigger on the server because it's been changed, as opposed to just appended to, you'll end up with a garbled file. Wget has no way of verifying that the local file is really a valid prefix of the remote file. You need to be especially careful of this when using `-c' in conjunction with `-r', since every file will be considered as an "incomplete download" candidate.

Another instance where you'll get a garbled file if you try to use `-c' is if you have a lame HTTP proxy that inserts a "transfer interrupted" string into the local file. In the future a "rollback" option may be added to deal with this case.

Note that `-c' only works with FTP servers and with HTTP servers that support the Range header.

`--progress=type'

Select the type of the progress indicator you wish to use. Legal indicators are "dot" and "bar".

The "bar" indicator is used by default. It draws an ASCII progress bar graphics (a.k.a "thermometer" display) indicating the status of retrieval. If the output is not a TTY, the "dot" bar will be used by default.

Use `--progress=dot' to switch to the "dot" display. It traces the retrieval by printing dots on the screen, each dot representing a fixed amount of downloaded data.

When using the dotted retrieval, you may also set the style by specifying the type as `dot:style'. Different styles assign different meaning to one dot. With the default style each dot represents 1K, there are ten dots in a cluster and 50 dots in a line. The binary style has a more "computer"-like orientation--8K dots, 16-dots clusters and 48 dots per line (which makes for 384K lines). The mega style is suitable for downloading very large files--each dot represents 64K retrieved, there are eight dots in a cluster, and 48 dots on each line (so each line contains 3M).

Note that you can set the default style using the progress command in `.wgetrc'. That setting may be overridden from the command line. The exception is that, when the output is not a TTY, the "dot" progress will be favored over "bar". To force the bar output, use `--progress=bar:force'.

`-N'

`--timestamping'

Turn on time-stamping. See section 5. Time-Stamping, for details.

`-S'

`--server-response'

Print the headers sent by HTTP servers and responses sent by FTP servers.

`--spider'

When invoked with this option, Wget will behave as a Web spider, which means that it will not download the pages, just check that they are there. You can use it to check your bookmarks, e.g. with:

wget --spider --force-html -i bookmarks.html

This feature needs much more work for Wget to get close to the functionality of real WWW spiders.

`-T seconds'

`--timeout=seconds'

Set the read timeout to seconds seconds. Whenever a network read is issued, the file descriptor is checked for a timeout, which could otherwise leave a pending connection (uninterrupted read). The default timeout is 900 seconds (fifteen minutes). Setting timeout to 0 will disable checking for timeouts.

Please do not lower the default timeout value with this option unless you know what you are doing.

`--limit-rate=amount'

Limit the download speed to amount bytes per second. Amount may be expressed in bytes, kilobytes with the `k' suffix, or megabytes with the `m' suffix. For example, `--limit-rate=20k' will limit the retrieval rate to 20KB/s. This kind of thing is useful when, for whatever reason, you don't want Wget to consume the entire evailable bandwidth.

Note that Wget implementeds the limiting by sleeping the appropriate amount of time after a network read that took less time than specified by the rate. Eventually this strategy causes the TCP transfer to slow down to approximately the specified rate. However, it takes some time for this balance to be achieved, so don't be surprised if limiting the rate doesn't work with very small files. Also, the "sleeping" strategy will misfire when an extremely small bandwidth, say less than 1.5KB/s, is specified.

`-w seconds'

`--wait=seconds'

Wait the specified number of seconds between the retrievals. Use of this option is recommended, as it lightens the server load by making the requests less frequent. Instead of in seconds, the time can be specified in minutes using the m suffix, in hours using h suffix, or in days using d suffix.

Specifying a large value for this option is useful if the network or the destination host is down, so that Wget can wait long enough to reasonably expect the network error to be fixed before the retry.

`--waitretry=seconds'

If you don't want Wget to wait between every retrieval, but only between retries of failed downloads, you can use this option. Wget will use linear backoff, waiting 1 second after the first failure on a given file, then waiting 2 seconds after the second failure on that file, up to the maximum number of seconds you specify. Therefore, a value of 10 will actually make Wget wait up to (1 + 2 + ... + 10) = 55 seconds per file.

Note that this option is turned on by default in the global `wgetrc' file.

`--random-wait'

Some web sites may perform log analysis to identify retrieval programs such as Wget by looking for statistically significant similarities in the time between requests. This option causes the time between requests to vary between 0 and 2 * wait seconds, where wait was specified using the `-w' or `--wait' options, in order to mask Wget's presence from such analysis.

A recent article in a publication devoted to development on a popular consumer platform provided code to perform this analysis on the fly. Its author suggested blocking at the class C address level to ensure automated retrieval programs were blocked despite changing DHCP-supplied addresses.

The `--random-wait' option was inspired by this ill-advised recommendation to block many unrelated users from a web site due to the actions of one.

`-Y on/off'

`--proxy=on/off'

Turn proxy support on or off. The proxy is on by default if the appropriate environmental variable is defined.

`-Q quota'

`--quota=quota'

Specify download quota for automatic retrievals. The value can be specified in bytes (default), kilobytes (with `k' suffix), or megabytes (with `m' suffix).

Note that quota will never affect downloading a single file. So if you specify `wget -Q10k ftp://wuarchive.wustl.edu/ls-lR.gz', all of the `ls-lR.gz' will be downloaded. The same goes even when several URLs are specified on the command-line. However, quota is respected when retrieving either recursively, or from an input file. Thus you may safely type `wget -Q2m -i sites'---download will be aborted when the quota is exceeded.

Setting quota to 0 or to `inf' unlimits the download quota.