Wget is non-interactive, meaning that it can work in the background, while the user is not logged on. This allows you to start a retrieval and disconnect from the system, letting Wget finish the work. By contrast, most of the Web browsers require constant user's presence, which can be a great hindrance when transferring a lot of data.
Wget can follow links in HTML, XHTML, and CSS pages, to create local versions of remote web sites, fully recreating the directory structure of the original site. This is sometimes referred to as ``recursive downloading.'' While doing that, Wget respects the Robot Exclusion Standard (/robots.txt). Wget can be instructed to convert the links in downloaded files to point at the local files, for offline viewing.
Wget has been designed for robustness over slow or unstable network connections; if a download fails due to a network problem, it will keep retrying until the whole file has been retrieved. If the server supports regetting, it will instruct the server to continue the download from where it left off.
Wget does not support Client Revocation Lists (CRLs) so the HTTPS certificate you are connecting to might be revoked by the siteowner.
wget -r --tries=10 http://fly.srk.fer.hr/ -o log
The space between the option accepting an argument and the argument may be omitted. Instead of -o log you can write -olog.
You may put several options that do not require arguments together, like:
wget -drc <URL>
This is completely equivalent to:
wget -d -r -c <URL>
Since the options can be specified after the arguments, you may terminate them with --. So the following will try to download URL -x, reporting failure to log:
wget -o log -- -x
The options that accept comma-separated lists all respect the convention that specifying an empty list clears its value. This can be useful to clear the .wgetrc settings. For instance, if your .wgetrc sets "exclude_directories" to /cgi-bin, the following example will first reset it, and then set it to exclude /~nobody and /~somebody. You can also clear the lists in .wgetrc.
wget -X " -X /~nobody,/~somebody
Most options that do not accept arguments are boolean options, so named because their state can be captured with a yes-or-no (``boolean'') variable. For example, --follow-ftp tells Wget to follow FTP links from HTML files and, on the other hand, --no-glob tells it not to perform file globbing on FTP URLs. A boolean option is either affirmative or negative (beginning with --no). All such options share several properties.
Unless stated otherwise, it is assumed that the default behavior is the opposite of what the option accomplishes. For example, the documented existence of --follow-ftp assumes that the default is to not follow FTP links from HTML pages.
Affirmative options can be negated by prepending the --no- to the option name; negative options can be negated by omitting the --no- prefix. This might seem superfluous---if the default for an affirmative option is to not do something, then why provide a way to explicitly turn it off? But the startup file may in fact change the default. For instance, using "follow_ftp = on" in .wgetrc makes Wget follow FTP links by default, and using --no-follow-ftp is the only way to restore the factory default from the command line.
If this function is used, no URLs need be present on the command line. If there are URLs both on the command line and in an input file, those on the command lines will be the first ones to be retrieved. If --force-html is not specified, then file should consist of a series of URLs, one per line.
However, if you specify --force-html, the document will be regarded as html. In that case you may have problems with relative links, which you can solve either by adding "<base href="url">" to the documents or by specifying --base=url on the command line.
If the file is an external one, the document will be automatically treated as html if the Content-Type matches text/html. Furthermore, the file's location will be implicitly used as base href if none was specified.
For instance, if you specify http://foo/bar/a.html for URL, and Wget reads ../baz/b.html from the input file, it would be resolved to http://foo/baz/b.html.
Use of -O is not intended to mean simply "use the name file instead of the one in the URL;" rather, it is analogous to shell redirection: wget -O file http://foo is intended to work like wget -O - http://foo > file; file will be truncated immediately, and all downloaded content will be written there.
For this reason, -N (for timestamp-checking) is not supported in combination with -O: since file is always newly created, it will always have a very new timestamp. A warning will be issued if this combination is used.
Similarly, using -r or -p with -O may not work as you expect: Wget won't just download the first file to file and then download the rest to their normal names: all downloaded content will be placed in file. This was disabled in version 1.11, but has been reinstated (with a warning) in 1.11.2, as there are some cases where this behavior can actually have some use.
A combination with -nc is only accepted if the given output file does not exist.
Note that a combination with -k is only permitted when downloading a single document, as in that case it will just convert all relative URIs to external ones; -k makes no sense for multiple URIs when they're all being downloaded to a single file; -k can be used only when the output is a regular file.
When running Wget without -N, -nc, -r, or -p, 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. (This is also the behavior with -nd, even if -r or -p are in effect.) 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 or -p, but without -N, -nd, 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 or -p, 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. -nc may not be specified at the same time as -N.
A combination with -O/--output-document is only accepted if the given output file does not exist.
Note that when -nc is specified, files with the suffixes .html or .htm will be loaded from the local disk and parsed as if they had been retrieved from the Web.
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.
--start-pos has higher precedence over --continue. When --start-pos and --continue are both specified, wget will emit a warning then proceed as if --continue was absent.
Server support for continued download is required, otherwise --start-pos cannot help. See -c for details.
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.
The progress type can also take one or more parameters. The parameters vary based on the type selected. Parameters to type are passed by appending them to the type sperated by a colon (:) like this: --progress=type:parameter1:parameter2.
When using the dotted retrieval, you may 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 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). If "mega" is not enough then you can use the "giga" style---each dot represents 1M retrieved, there are eight dots in a cluster, and 32 dots on each line (so each line contains 32M).
With --progress=bar, there are currently two possible parameters, force and noscroll.
When the output is not a TTY, the progress bar always falls back to ``dot'', even if --progress=bar was passed to Wget during invokation. This behaviour can be overridden and the ``bar'' output forced by using the ``force'' parameter as --progress=bar:force.
By default, the bar style progress bar scroll the name of the file from left to right for the file being downloaded if the filename exceeds the maximum length allotted for its display. In certain cases, such as with --progress=bar:force, one may not want the scrolling filename in the progress bar. By passing the ``noscroll'' parameter, Wget can be forced to display as much of the filename as possible without scrolling through it.
Note that you can set the default style using the "progress" command in .wgetrc. That setting may be overridden from the command line. For example, to force the bar output without scrolling, use --progress=bar:force:noscroll.
By default, wget only displays the progress bar in verbose mode. One may however, want wget to display the progress bar on screen in conjunction with any other verbosity modes like --no-verbose or --quiet. This is often a desired a property when invoking wget to download several small/large files. In such a case, wget could simply be invoked with this parameter to get a much cleaner output on the screen.
This option will also force the progress bar to be printed to stderr when used alongside the --logfile option.
By default, when a file is downloaded, its timestamps are set to match those from the remote file. This allows the use of --timestamping on subsequent invocations of wget. However, it is sometimes useful to base the local file's timestamp on when it was actually downloaded; for that purpose, the --no-use-server-timestamps option has been provided.
wget --spider --force-html -i bookmarks.html
This feature needs much more work for Wget to get close to the functionality of real web spiders.
When interacting with the network, Wget can check for timeout and abort the operation if it takes too long. This prevents anomalies like hanging reads and infinite connects. The only timeout enabled by default is a 900-second read timeout. Setting a timeout to 0 disables it altogether. Unless you know what you are doing, it is best not to change the default timeout settings.
All timeout-related options accept decimal values, as well as subsecond values. For example, 0.1 seconds is a legal (though unwise) choice of timeout. Subsecond timeouts are useful for checking server response times or for testing network latency.
Of course, the remote server may choose to terminate the connection sooner than this option requires. The default read timeout is 900 seconds.
This option allows the use of decimal numbers, usually in conjunction with power suffixes; for example, --limit-rate=2.5k is a legal value.
Note that Wget implements 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 may take some time for this balance to be achieved, so don't be surprised if limiting the rate doesn't work well with very small files.
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. The waiting interval specified by this function is influenced by "--random-wait", which see.
By default, Wget will assume a value of 10 seconds.
A 2001 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.
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.
However, it has been reported that in some situations it is not desirable to cache host names, even for the duration of a short-running application like Wget. With this option Wget issues a new DNS lookup (more precisely, a new call to "gethostbyname" or "getaddrinfo") each time it makes a new connection. Please note that this option will not affect caching that might be performed by the resolving library or by an external caching layer, such as NSCD.
If you don't understand exactly what this option does, you probably won't need it.
By default, Wget escapes the characters that are not valid or safe as part of file names on your operating system, as well as control characters that are typically unprintable. This option is useful for changing these defaults, perhaps because you are downloading to a non-native partition, or because you want to disable escaping of the control characters, or you want to further restrict characters to only those in the ASCII range of values.
The modes are a comma-separated set of text values. The acceptable values are unix, windows, nocontrol, ascii, lowercase, and uppercase. The values unix and windows are mutually exclusive (one will override the other), as are lowercase and uppercase. Those last are special cases, as they do not change the set of characters that would be escaped, but rather force local file paths to be converted either to lower- or uppercase.
When ``unix'' is specified, Wget escapes the character / and the control characters in the ranges 0--31 and 128--159. This is the default on Unix-like operating systems.
When ``windows'' is given, Wget escapes the characters \, |, /, :, ?, ", *, <, >, and the control characters in the ranges 0--31 and 128--159. In addition to this, Wget in Windows mode uses + instead of : to separate host and port in local file names, and uses @ instead of ? to separate the query portion of the file name from the rest. Therefore, a URL that would be saved as www.xemacs.org:4300/search.pl?input=blah in Unix mode would be saved as www.xemacs.org+4300/search.pl@input=blah in Windows mode. This mode is the default on Windows.
If you specify nocontrol, then the escaping of the control characters is also switched off. This option may make sense when you are downloading URLs whose names contain UTF-8 characters, on a system which can save and display filenames in UTF-8 (some possible byte values used in UTF-8 byte sequences fall in the range of values designated by Wget as ``controls'').
The ascii mode is used to specify that any bytes whose values are outside the range of ASCII characters (that is, greater than 127) shall be escaped. This can be useful when saving filenames whose encoding does not match the one used locally.
Neither options should be needed normally. By default, an IPv6-aware Wget will use the address family specified by the host's DNS record. If the DNS responds with both IPv4 and IPv6 addresses, Wget will try them in sequence until it finds one it can connect to. (Also see "--prefer-family" option described below.)
These options can be used to deliberately force the use of IPv4 or IPv6 address families on dual family systems, usually to aid debugging or to deal with broken network configuration. Only one of --inet6-only and --inet4-only may be specified at the same time. Neither option is available in Wget compiled without IPv6 support.
This avoids spurious errors and connect attempts when accessing hosts that resolve to both IPv6 and IPv4 addresses from IPv4 networks. For example, www.kame.net resolves to 2001:200:0:8002:203:47ff:fea5:3085 and to 203.178.141.194. When the preferred family is "IPv4", the IPv4 address is used first; when the preferred family is "IPv6", the IPv6 address is used first; if the specified value is "none", the address order returned by DNS is used without change.
Unlike -4 and -6, this option doesn't inhibit access to any address family, it only changes the order in which the addresses are accessed. Also note that the reordering performed by this option is stable---it doesn't affect order of addresses of the same family. That is, the relative order of all IPv4 addresses and of all IPv6 addresses remains intact in all cases.
You can set the default state of IRI support using the "iri" command in .wgetrc. That setting may be overridden from the command line.
Wget use the function "nl_langinfo()" and then the "CHARSET" environment variable to get the locale. If it fails, ASCII is used.
You can set the default local encoding using the "local_encoding" command in .wgetrc. That setting may be overridden from the command line.
For HTTP, remote encoding can be found in HTTP "Content-Type" header and in HTML "Content-Type http-equiv" meta tag.
You can set the default encoding using the "remoteencoding" command in .wgetrc. That setting may be overridden from the command line.
Take, for example, the directory at ftp://ftp.xemacs.org/pub/xemacs/. If you retrieve it with -r, it will be saved locally under ftp.xemacs.org/pub/xemacs/. While the -nH option can remove the ftp.xemacs.org/ part, you are still stuck with pub/xemacs. This is where --cut-dirs comes in handy; it makes Wget not ``see'' number remote directory components. Here are several examples of how --cut-dirs option works.
No options -> ftp.xemacs.org/pub/xemacs/
-nH -> pub/xemacs/
-nH --cut-dirs=1 -> xemacs/
-nH --cut-dirs=2 -> .
--cut-dirs=1 -> ftp.xemacs.org/xemacs/
...
If you just want to get rid of the directory structure, this option is similar to a combination of -nd and -P. However, unlike -nd, --cut-dirs does not lose with subdirectories---for instance, with -nH --cut-dirs=1, a beta/ subdirectory will be placed to xemacs/beta, as one would expect.
Note that filenames changed in this way will be re-downloaded every time you re-mirror a site, because Wget can't tell that the local X.html file corresponds to remote URL X (since it doesn't yet know that the URL produces output of type text/html or application/xhtml+xml.
As of version 1.12, Wget will also ensure that any downloaded files of type text/css end in the suffix .css, and the option was renamed from --html-extension, to better reflect its new behavior. The old option name is still acceptable, but should now be considered deprecated.
At some point in the future, this option may well be expanded to include suffixes for other types of content, including content types that are not parsed by Wget.
Another way to specify username and password is in the URL itself. Either method reveals your password to anyone who bothers to run "ps". To prevent the passwords from being seen, store them in .wgetrc or .netrc, and make sure to protect those files from other users with "chmod". If the passwords are really important, do not leave them lying in those files either---edit the files and delete them after Wget has started the download.
This option is useful when, for some reason, persistent (keep-alive) connections don't work for you, for example due to a server bug or due to the inability of server-side scripts to cope with the connections.
Caching is allowed by default.
You will typically use this option when mirroring sites that require that you be logged in to access some or all of their content. The login process typically works by the web server issuing an HTTP cookie upon receiving and verifying your credentials. The cookie is then resent by the browser when accessing that part of the site, and so proves your identity.
Mirroring such a site requires Wget to send the same cookies your browser sends when communicating with the site. This is achieved by --load-cookies---simply point Wget to the location of the cookies.txt file, and it will send the same cookies your browser would send in the same situation. Different browsers keep textual cookie files in different locations:
If you cannot use --load-cookies, there might still be an alternative. If your browser supports a ``cookie manager'', you can use it to view the cookies used when accessing the site you're mirroring. Write down the name and value of the cookie, and manually instruct Wget to send those cookies, bypassing the ``official'' cookie support:
wget --no-cookies --header "Cookie: <name>=<value>"
Since the cookie file format does not normally carry session cookies, Wget marks them with an expiry timestamp of 0. Wget's --load-cookies recognizes those as session cookies, but it might confuse other browsers. Also note that cookies so loaded will be treated as other session cookies, which means that if you want --save-cookies to preserve them again, you must use --keep-session-cookies again.
With this option, Wget will ignore the "Content-Length" header---as if it never existed.
You may define more than one additional header by specifying --header more than once.
wget --header='Accept-Charset: iso-8859-2' \
--header='Accept-Language: hr' \
http://fly.srk.fer.hr/
Specification of an empty string as the header value will clear all previous user-defined headers.
As of Wget 1.10, this option can be used to override headers otherwise generated automatically. This example instructs Wget to connect to localhost, but to specify foo.bar in the "Host" header:
wget --header="Host: foo.bar" http://localhost/
In versions of Wget prior to 1.10 such use of --header caused sending of duplicate headers.
Security considerations similar to those with --http-password pertain here as well.
The HTTP protocol allows the clients to identify themselves using a "User-Agent" header field. This enables distinguishing the WWW software, usually for statistical purposes or for tracing of protocol violations. Wget normally identifies as Wget/version, version being the current version number of Wget.
However, some sites have been known to impose the policy of tailoring the output according to the "User-Agent"-supplied information. While this is not such a bad idea in theory, it has been abused by servers denying information to clients other than (historically) Netscape or, more frequently, Microsoft Internet Explorer. This option allows you to change the "User-Agent" line issued by Wget. Use of this option is discouraged, unless you really know what you are doing.
Specifying empty user agent with --user-agent="" instructs Wget not to send the "User-Agent" header in HTTP requests.
Please note that wget does not require the content to be of the form "key1=value1&key2=value2", and neither does it test for it. Wget will simply transmit whatever data is provided to it. Most servers however expect the POST data to be in the above format when processing HTML Forms.
When sending a POST request using the --post-file option, Wget treats the file as a binary file and will send every character in the POST request without stripping trailing newline or formfeed characters. Any other control characters in the text will also be sent as-is in the POST request.
Please be aware that Wget needs to know the size of the POST data in advance. Therefore the argument to "--post-file" must be a regular file; specifying a FIFO or something like /dev/stdin won't work. It's not quite clear how to work around this limitation inherent in HTTP/1.0. Although HTTP/1.1 introduces chunked transfer that doesn't require knowing the request length in advance, a client can't use chunked unless it knows it's talking to an HTTP/1.1 server. And it can't know that until it receives a response, which in turn requires the request to have been completed --- a chicken-and-egg problem.
Note: As of version 1.15 if Wget is redirected after the POST request is completed, its behaviour will depend on the response code returned by the server. In case of a 301 Moved Permanently, 302 Moved Temporarily or 307 Temporary Redirect, Wget will, in accordance with RFC2616, continue to send a POST request. In case a server wants the client to change the Request method upon redirection, it should send a 303 See Other response code.
This example shows how to log in to a server using POST and then proceed to download the desired pages, presumably only accessible to authorized users:
# Log in to the server. This can be done only once.
wget --save-cookies cookies.txt \
--post-data 'user=foo&password=bar' \
http://server.com/auth.php
# Now grab the page or pages we care about.
wget --load-cookies cookies.txt \
-p http://server.com/interesting/article.php
If the server is using session cookies to track user authentication, the above will not work because --save-cookies will not save them (and neither will browsers) and the cookies.txt file will be empty. In that case use --keep-session-cookies along with --save-cookies to force saving of session cookies.
Currently, --body-file is not for transmitting files as a whole. Wget does not currently support "multipart/form-data" for transmitting data; only "application/x-www-form-urlencoded". In the future, this may be changed so that wget sends the --body-file as a complete file instead of sending its contents to the server. Please be aware that Wget needs to know the contents of BODY Data in advance, and hence the argument to --body-file should be a regular file. See --post-file for a more detailed explanation. Only one of --body-data and --body-file should be specified.
If Wget is redirected after the request is completed, Wget will suspend the current method and send a GET request till the redirection is completed. This is true for all redirection response codes except 307 Temporary Redirect which is used to explicitly specify that the request method should not change. Another exception is when the method is set to "POST", in which case the redirection rules specified under --post-data are followed.
This option is useful for some file-downloading CGI programs that use "Content-Disposition" headers to describe what the name of a downloaded file should be.
Use of this option is not recommended, and is intended only to support some few obscure servers, which never send HTTP authentication challenges, but accept unsolicited auth info, say, in addition to form-based authentication.
Specifying SSLv2, SSLv3, TLSv1, TLSv1_1 or TLSv1_2 forces the use of the corresponding protocol. This is useful when talking to old and buggy SSL server implementations that make it hard for the underlying SSL library to choose the correct protocol version. Fortunately, such servers are quite rare.
Specifying PFS enforces the use of the so-called Perfect Forward Security cipher suites. In short, PFS adds security by creating a one-time key for each SSL connection. It has a bit more CPU impact on client and server. We use known to be secure ciphers (e.g. no MD4) and the TLS protocol.
As of Wget 1.10, the default is to verify the server's certificate against the recognized certificate authorities, breaking the SSL handshake and aborting the download if the verification fails. Although this provides more secure downloads, it does break interoperability with some sites that worked with previous Wget versions, particularly those using self-signed, expired, or otherwise invalid certificates. This option forces an ``insecure'' mode of operation that turns the certificate verification errors into warnings and allows you to proceed.
If you encounter ``certificate verification'' errors or ones saying that ``common name doesn't match requested host name'', you can use this option to bypass the verification and proceed with the download. Only use this option if you are otherwise convinced of the site's authenticity, or if you really don't care about the validity of its certificate. It is almost always a bad idea not to check the certificates when transmitting confidential or important data. For self-signed/internal certificates, you should download the certificate and verify against that instead of forcing this insecure mode. If you are really sure of not desiring any certificate verification, you can specify --check-certificate=quiet to tell wget to not print any warning about invalid certificates, albeit in most cases this is the wrong thing to do.
Without this option Wget looks for CA certificates at the system-specified locations, chosen at OpenSSL installation time.
Without this option Wget looks for CA certificates at the system-specified locations, chosen at OpenSSL installation time.
On such systems the SSL library needs an external source of randomness to initialize. Randomness may be provided by EGD (see --egd-file below) or read from an external source specified by the user. If this option is not specified, Wget looks for random data in $RANDFILE or, if that is unset, in $HOME/.rnd.
If you're getting the ``Could not seed OpenSSL PRNG; disabling SSL.'' error, you should provide random data using some of the methods described above.
OpenSSL allows the user to specify his own source of entropy using the "RAND_FILE" environment variable. If this variable is unset, or if the specified file does not produce enough randomness, OpenSSL will read random data from EGD socket specified using this option.
If this option is not specified (and the equivalent startup command is not used), EGD is never contacted. EGD is not needed on modern Unix systems that support /dev/urandom.
The Wget's HSTS database is a plain text file. Each line contains an HSTS entry (ie. a site that has issued a "Strict-Transport-Security" header and that therefore has specified a concrete HSTS policy to be applied). Lines starting with a dash ("#") are ignored by Wget. Please note that in spite of this convenient human-readability hand-hacking the HSTS database is generally not a good idea.
An HSTS entry line consists of several fields separated by one or more whitespace:
"<hostname> SP [<port>] SP <include subdomains> SP <created> SP <max-age>"
The hostname and port fields indicate the hostname and port to which the given HSTS policy applies. The port field may be zero, and it will, in most of the cases. That means that the port number will not be taken into account when deciding whether such HSTS policy should be applied on a given request (only the hostname will be evaluated). When port is different to zero, both the target hostname and the port will be evaluated and the HSTS policy will only be applied if both of them match. This feature has been included for testing/development purposes only. The Wget testsuite (in testenv/) creates HSTS databases with explicit ports with the purpose of ensuring Wget's correct behaviour. Applying HSTS policies to ports other than the default ones is discouraged by RFC 6797 (see Appendix B ``Differences between HSTS Policy and Same-Origin Policy''). Thus, this functionality should not be used in production environments and port will typically be zero. The last three fields do what they are expected to. The field include_subdomains can either be 1 or 0 and it signals whether the subdomains of the target domain should be part of the given HSTS policy as well. The created and max-age fields hold the timestamp values of when such entry was created (first seen by Wget) and the HSTS-defined value 'max-age', which states how long should that HSTS policy remain active, measured in seconds elapsed since the timestamp stored in created. Once that time has passed, that HSTS policy will no longer be valid and will eventually be removed from the database.
If you supply your own HSTS database via --hsts-file, be aware that Wget may modify the provided file if any change occurs between the HSTS policies requested by the remote servers and those in the file. When Wget exists, it effectively updates the HSTS database by rewriting the database file with the new entries.
If the supplied file does not exist, Wget will create one. This file will contain the new HSTS entries. If no HSTS entries were generated (no "Strict-Transport-Security" headers were sent by any of the servers) then no file will be created, not even an empty one. This behaviour applies to the default database file (~/.wget-hsts) as well: it will not be created until some server enforces an HSTS policy.
Care is taken not to override possible changes made by other Wget processes at the same time over the HSTS database. Before dumping the updated HSTS entries on the file, Wget will re-read it and merge the changes.
Using a custom HSTS database and/or modifying an existing one is discouraged. For more information about the potential security threats arised from such practice, see section 14 ``Security Considerations'' of RFC 6797, specially section 14.9 ``Creative Manipulation of HSTS Policy Store''.
Another way to specify username and password is in the URL itself. Either method reveals your password to anyone who bothers to run "ps". To prevent the passwords from being seen, store them in .wgetrc or .netrc, and make sure to protect those files from other users with "chmod". If the passwords are really important, do not leave them lying in those files either---edit the files and delete them after Wget has started the download.
Note that even though Wget writes to a known filename for this file, this is not a security hole in the scenario of a user making .listing a symbolic link to /etc/passwd or something and asking "root" to run Wget in his or her directory. Depending on the options used, either Wget will refuse to write to .listing, making the globbing/recursion/time-stamping operation fail, or the symbolic link will be deleted and replaced with the actual .listing file, or the listing will be written to a .listing.number file.
Even though this situation isn't a problem, though, "root" should never run Wget in a non-trusted user's directory. A user could do something as simple as linking index.html to /etc/passwd and asking "root" to run Wget with -N or -r so the file will be overwritten.
wget ftp://gnjilux.srk.fer.hr/*.msg
By default, globbing will be turned on if the URL contains a globbing character. This option may be used to turn globbing on or off permanently.
You may have to quote the URL to protect it from being expanded by your shell. Globbing makes Wget look for a directory listing, which is system-specific. This is why it currently works only with Unix FTP servers (and the ones emulating Unix "ls" output).
If the machine is connected to the Internet directly, both passive and active FTP should work equally well. Behind most firewall and NAT configurations passive FTP has a better chance of working. However, in some rare firewall configurations, active FTP actually works when passive FTP doesn't. If you suspect this to be the case, use this option, or set "passive_ftp=off" in your init file.
When --retr-symlinks=no is specified, the linked-to file is not downloaded. Instead, a matching symbolic link is created on the local filesystem. The pointed-to file will not be retrieved unless this recursive retrieval would have encountered it separately and downloaded it anyway. This option poses a security risk where a malicious FTP Server may cause Wget to write to files outside of the intended directories through a specially crafted .LISTING file.
Note that when retrieving a file (not a directory) because it was specified on the command-line, rather than because it was recursed to, this option has no effect. Symbolic links are always traversed in this case.
wget -r -nd --delete-after http://whatever.com/~popular/page/
The -r option is to retrieve recursively, and -nd to not create directories.
Note that --delete-after deletes files on the local machine. It does not issue the DELE command to remote FTP sites, for instance. Also note that when --delete-after is specified, --convert-links is ignored, so .orig files are simply not created in the first place.
Each link will be changed in one of the two ways:
Example: if the downloaded file /foo/doc.html links to /bar/img.gif, also downloaded, then the link in doc.html will be modified to point to ../bar/img.gif. This kind of transformation works reliably for arbitrary combinations of directories.
Example: if the downloaded file /foo/doc.html links to /bar/img.gif (or to ../bar/img.gif), then the link in doc.html will be modified to point to http://hostname/bar/img.gif.
Because of this, local browsing works reliably: if a linked file was downloaded, the link will refer to its local name; if it was not downloaded, the link will refer to its full Internet address rather than presenting a broken link. The fact that the former links are converted to relative links ensures that you can move the downloaded hierarchy to another directory.
Note that only at the end of the download can Wget know which links have been downloaded. Because of that, the work done by -k will be performed at the end of all the downloads.
It works particularly well in conjunction with --adjust-extension, although this coupling is not enforced. It proves useful to populate Internet caches with files downloaded from different hosts.
Example: if some link points to //foo.com/bar.cgi?xyz with --adjust-extension asserted and its local destination is intended to be ./foo.com/bar.cgi?xyz.css, then the link would be converted to //foo.com/bar.cgi?xyz.css. Note that only the filename part has been modified. The rest of the URL has been left untouched, including the net path ("//") which would otherwise be processed by Wget and converted to the effective scheme (ie. "http://").
Ordinarily, when downloading a single HTML page, any requisite documents that may be needed to display it properly are not downloaded. Using -r together with -l can help, but since Wget does not ordinarily distinguish between external and inlined documents, one is generally left with ``leaf documents'' that are missing their requisites.
For instance, say document 1.html contains an "<IMG>" tag referencing 1.gif and an "<A>" tag pointing to external document 2.html. Say that 2.html is similar but that its image is 2.gif and it links to 3.html. Say this continues up to some arbitrarily high number.
If one executes the command:
wget -r -l 2 http://<site>/1.html
then 1.html, 1.gif, 2.html, 2.gif, and 3.html will be downloaded. As you can see, 3.html is without its requisite 3.gif because Wget is simply counting the number of hops (up to 2) away from 1.html in order to determine where to stop the recursion. However, with this command:
wget -r -l 2 -p http://<site>/1.html
all the above files and 3.html's requisite 3.gif will be downloaded. Similarly,
wget -r -l 1 -p http://<site>/1.html
will cause 1.html, 1.gif, 2.html, and 2.gif to be downloaded. One might think that:
wget -r -l 0 -p http://<site>/1.html
would download just 1.html and 1.gif, but unfortunately this is not the case, because -l 0 is equivalent to -l inf---that is, infinite recursion. To download a single HTML page (or a handful of them, all specified on the command-line or in a -i URL input file) and its (or their) requisites, simply leave off -r and -l:
wget -p http://<site>/1.html
Note that Wget will behave as if -r had been specified, but only that single page and its requisites will be downloaded. Links from that page to external documents will not be followed. Actually, to download a single page and all its requisites (even if they exist on separate websites), and make sure the lot displays properly locally, this author likes to use a few options in addition to -p:
wget -E -H -k -K -p http://<site>/<document>
To finish off this topic, it's worth knowing that Wget's idea of an external document link is any URL specified in an "<A>" tag, an "<AREA>" tag, or a "<LINK>" tag other than "<LINK REL="stylesheet">".
According to specifications, HTML comments are expressed as SGML declarations. Declaration is special markup that begins with <! and ends with >, such as <!DOCTYPE ...>, that may contain comments between a pair of -- delimiters. HTML comments are ``empty declarations'', SGML declarations without any non-comment text. Therefore, <!--foo--> is a valid comment, and so is <!--one--- --two-->, but <!--1--2--> is not.
On the other hand, most HTML writers don't perceive comments as anything other than text delimited with <!-- and -->, which is not quite the same. For example, something like <!------------> works as a valid comment as long as the number of dashes is a multiple of four (!). If not, the comment technically lasts until the next --, which may be at the other end of the document. Because of this, many popular browsers completely ignore the specification and implement what users have come to expect: comments delimited with <!-- and -->.
Until version 1.9, Wget interpreted comments strictly, which resulted in missing links in many web pages that displayed fine in browsers, but had the misfortune of containing non-compliant comments. Beginning with version 1.9, Wget has joined the ranks of clients that implements ``naive'' comments, terminating each comment at the first occurrence of -->.
If, for whatever reason, you want strict comment parsing, use this option to turn it on.
In the past, this option was the best bet for downloading a single page and its requisites, using a command-line like:
wget --ignore-tags=a,area -H -k -K -r http://<site>/<document>
However, the author of this option came across a page with tags like "<LINK REL="home" HREF="/">" and came to the realization that specifying tags to ignore was not enough. One can't just tell Wget to ignore "<LINK>", because then stylesheets will not be downloaded. Now the best bet for downloading a single page and its requisites is the dedicated --page-requisites option.
With the exceptions of 0 and 1, the lower-numbered exit codes take precedence over higher-numbered ones, when multiple types of errors are encountered.
In versions of Wget prior to 1.12, Wget's exit status tended to be unhelpful and inconsistent. Recursive downloads would virtually always return 0 (success), regardless of any issues encountered, and non-recursive fetches only returned the status corresponding to the most recently-attempted download.
Before actually submitting a bug report, please try to follow a few simple guidelines.
Also, while I will probably be interested to know the contents of your .wgetrc file, just dumping it into the debug message is probably a bad idea. Instead, you should first try to see if the bug repeats with .wgetrc moved out of the way. Only if it turns out that .wgetrc settings affect the bug, mail me the relevant parts of the file.
Note: please make sure to remove any potentially sensitive information from the debug log before sending it to the bug address. The "-d" won't go out of its way to collect sensitive information, but the log will contain a fairly complete transcript of Wget's communication with the server, which may include passwords and pieces of downloaded data. Since the bug address is publically archived, you may assume that all bug reports are visible to the public.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''.