2.10 Recursive Retrieval Options

‘-r’

‘--recursive’

Turn on recursive retrieving. See section Recursive Download, for more details. The default maximum depth is 5.

‘-l depth’

‘--level=depth’

Specify recursion maximum depth level depth (see section Recursive Download).

‘--delete-after’

This option tells Wget to delete every single file it downloads, after having done so. It is useful for pre-fetching popular pages through a proxy, e.g.:

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.

‘-k’

‘--convert-links’

After the download is complete, convert the links in the document to make them suitable for local viewing. This affects not only the visible hyperlinks, but any part of the document that links to external content, such as embedded images, links to style sheets, hyperlinks to non-HTML content, etc.

Each link will be changed in one of the two ways:

• The links to files that have been downloaded by Wget will be changed to refer to the file they point to as a relative link.

  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.

• The links to files that have not been downloaded by Wget will be changed to include host name and absolute path of the location they point to.

  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.

‘-K’

‘--backup-converted’

When converting a file, back up the original version with a ‘.orig’ suffix. Affects the behavior of ‘-N’ (see section HTTP Time-Stamping Internals).

‘-m’

‘--mirror’

Turn on options suitable for mirroring. This option turns on recursion and time-stamping, sets infinite recursion depth and keeps FTP directory listings. It is currently equivalent to ‘-r -N -l inf --no-remove-listing’.

‘-p’

‘--page-requisites’

This option causes Wget to download all the files that are necessary to properly display a given HTML page. This includes such things as inlined images, sounds, and referenced stylesheets.

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">.

‘--strict-comments’

Turn on strict parsing of HTML comments. The default is to terminate comments at the first occurrence of ‘-->’.

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.

This document was generated on February 2, 2014 using texi2html 5.0.