[wget] / doc / wget.info-2

This is Info file wget.info, produced by Makeinfo version 1.68 from the
input file ./wget.texi.

INFO-DIR-SECTION Net Utilities
INFO-DIR-SECTION World Wide Web
START-INFO-DIR-ENTRY
* Wget: (wget).         The non-interactive network downloader.
END-INFO-DIR-ENTRY

   This file documents the the GNU Wget utility for downloading network
data.

   Copyright (C) 1996, 1997, 1998, 2000 Free Software Foundation, Inc.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the sections entitled "Copying" and "GNU General Public License"
are included exactly as in the original, and provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.

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File: wget.info,  Node: Time-Stamping,  Next: Startup File,  Prev: Following Links,  Up: Top

Time-Stamping
*************

   One of the most important aspects of mirroring information from the
Internet is updating your archives.

   Downloading the whole archive again and again, just to replace a few
changed files is expensive, both in terms of wasted bandwidth and money,
and the time to do the update.  This is why all the mirroring tools
offer the option of incremental updating.

   Such an updating mechanism means that the remote server is scanned in
search of "new" files.  Only those new files will be downloaded in the
place of the old ones.

   A file is considered new if one of these two conditions are met:

  1. A file of that name does not already exist locally.

  2. A file of that name does exist, but the remote file was modified
     more recently than the local file.

   To implement this, the program needs to be aware of the time of last
modification of both remote and local files.  Such information are
called the "time-stamps".

   The time-stamping in GNU Wget is turned on using `--timestamping'
(`-N') option, or through `timestamping = on' directive in `.wgetrc'.
With this option, for each file it intends to download, Wget will check
whether a local file of the same name exists.  If it does, and the
remote file is older, Wget will not download it.

   If the local file does not exist, or the sizes of the files do not
match, Wget will download the remote file no matter what the time-stamps
say.

* Menu:

* Time-Stamping Usage::
* HTTP Time-Stamping Internals::
* FTP Time-Stamping Internals::

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File: wget.info,  Node: Time-Stamping Usage,  Next: HTTP Time-Stamping Internals,  Prev: Time-Stamping,  Up: Time-Stamping

Time-Stamping Usage
===================

   The usage of time-stamping is simple.  Say you would like to
download a file so that it keeps its date of modification.

     wget -S http://www.gnu.ai.mit.edu/

   A simple `ls -l' shows that the time stamp on the local file equals
the state of the `Last-Modified' header, as returned by the server.  As
you can see, the time-stamping info is preserved locally, even without
`-N'.

   Several days later, you would like Wget to check if the remote file
has changed, and download it if it has.

     wget -N http://www.gnu.ai.mit.edu/

   Wget will ask the server for the last-modified date.  If the local
file is newer, the remote file will not be re-fetched.  However, if the
remote file is more recent, Wget will proceed fetching it normally.

   The same goes for FTP.  For example:

     wget ftp://ftp.ifi.uio.no/pub/emacs/gnus/*

   `ls' will show that the timestamps are set according to the state on
the remote server.  Reissuing the command with `-N' will make Wget
re-fetch *only* the files that have been modified.

   In both HTTP and FTP retrieval Wget will time-stamp the local file
correctly (with or without `-N') if it gets the stamps, i.e. gets the
directory listing for FTP or the `Last-Modified' header for HTTP.

   If you wished to mirror the GNU archive every week, you would use the
following command every week:

     wget --timestamping -r ftp://prep.ai.mit.edu/pub/gnu/

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File: wget.info,  Node: HTTP Time-Stamping Internals,  Next: FTP Time-Stamping Internals,  Prev: Time-Stamping Usage,  Up: Time-Stamping

HTTP Time-Stamping Internals
============================

   Time-stamping in HTTP is implemented by checking of the
`Last-Modified' header.  If you wish to retrieve the file `foo.html'
through HTTP, Wget will check whether `foo.html' exists locally.  If it
doesn't, `foo.html' will be retrieved unconditionally.

   If the file does exist locally, Wget will first check its local
time-stamp (similar to the way `ls -l' checks it), and then send a
`HEAD' request to the remote server, demanding the information on the
remote file.

   The `Last-Modified' header is examined to find which file was
modified more recently (which makes it "newer").  If the remote file is
newer, it will be downloaded; if it is older, Wget will give up.(1)

   When `--backup-converted' (`-K') is specified in conjunction with
`-N', server file `X' is compared to local file `X.orig', if extant,
rather than being compared to local file `X', which will always differ
if it's been converted by `--convert-links' (`-k').

   Arguably, HTTP time-stamping should be implemented using the
`If-Modified-Since' request.

   ---------- Footnotes ----------

   (1) As an additional check, Wget will look at the `Content-Length'
header, and compare the sizes; if they are not the same, the remote
file will be downloaded no matter what the time-stamp says.

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File: wget.info,  Node: FTP Time-Stamping Internals,  Prev: HTTP Time-Stamping Internals,  Up: Time-Stamping

FTP Time-Stamping Internals
===========================

   In theory, FTP time-stamping works much the same as HTTP, only FTP
has no headers--time-stamps must be received from the directory
listings.

   For each directory files must be retrieved from, Wget will use the
`LIST' command to get the listing.  It will try to analyze the listing,
assuming that it is a Unix `ls -l' listing, and extract the
time-stamps.  The rest is exactly the same as for HTTP.

   Assumption that every directory listing is a Unix-style listing may
sound extremely constraining, but in practice it is not, as many
non-Unix FTP servers use the Unixoid listing format because most (all?)
of the clients understand it.  Bear in mind that RFC959 defines no
standard way to get a file list, let alone the time-stamps.  We can
only hope that a future standard will define this.

   Another non-standard solution includes the use of `MDTM' command
that is supported by some FTP servers (including the popular
`wu-ftpd'), which returns the exact time of the specified file.  Wget
may support this command in the future.

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File: wget.info,  Node: Startup File,  Next: Examples,  Prev: Time-Stamping,  Up: Top

Startup File
************

   Once you know how to change default settings of Wget through command
line arguments, you may wish to make some of those settings permanent.
You can do that in a convenient way by creating the Wget startup
file--`.wgetrc'.

   Besides `.wgetrc' is the "main" initialization file, it is
convenient to have a special facility for storing passwords.  Thus Wget
reads and interprets the contents of `$HOME/.netrc', if it finds it.
You can find `.netrc' format in your system manuals.

   Wget reads `.wgetrc' upon startup, recognizing a limited set of
commands.

* Menu:

* Wgetrc Location::   Location of various wgetrc files.
* Wgetrc Syntax::     Syntax of wgetrc.
* Wgetrc Commands::   List of available commands.
* Sample Wgetrc::     A wgetrc example.

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File: wget.info,  Node: Wgetrc Location,  Next: Wgetrc Syntax,  Prev: Startup File,  Up: Startup File

Wgetrc Location
===============

   When initializing, Wget will look for a "global" startup file,
`/usr/local/etc/wgetrc' by default (or some prefix other than
`/usr/local', if Wget was not installed there) and read commands from
there, if it exists.

   Then it will look for the user's file.  If the environmental variable
`WGETRC' is set, Wget will try to load that file.  Failing that, no
further attempts will be made.

   If `WGETRC' is not set, Wget will try to load `$HOME/.wgetrc'.

   The fact that user's settings are loaded after the system-wide ones
means that in case of collision user's wgetrc *overrides* the
system-wide wgetrc (in `/usr/local/etc/wgetrc' by default).  Fascist
admins, away!

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File: wget.info,  Node: Wgetrc Syntax,  Next: Wgetrc Commands,  Prev: Wgetrc Location,  Up: Startup File

Wgetrc Syntax
=============

   The syntax of a wgetrc command is simple:

     variable = value

   The "variable" will also be called "command".  Valid "values" are
different for different commands.

   The commands are case-insensitive and underscore-insensitive.  Thus
`DIr__PrefiX' is the same as `dirprefix'.  Empty lines, lines beginning
with `#' and lines containing white-space only are discarded.

   Commands that expect a comma-separated list will clear the list on an
empty command.  So, if you wish to reset the rejection list specified in
global `wgetrc', you can do it with:

     reject =

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File: wget.info,  Node: Wgetrc Commands,  Next: Sample Wgetrc,  Prev: Wgetrc Syntax,  Up: Startup File

Wgetrc Commands
===============

   The complete set of commands is listed below, the letter after `='
denoting the value the command takes. It is `on/off' for `on' or `off'
(which can also be `1' or `0'), STRING for any non-empty string or N
for a positive integer.  For example, you may specify `use_proxy = off'
to disable use of proxy servers by default. You may use `inf' for
infinite values, where appropriate.

   Most of the commands have their equivalent command-line option
(*Note Invoking::), except some more obscure or rarely used ones.

accept/reject = STRING
     Same as `-A'/`-R' (*Note Types of Files::).

add_hostdir = on/off
     Enable/disable host-prefixed file names.  `-nH' disables it.

continue = on/off
     Enable/disable continuation of the retrieval - the same as `-c'
     (which enables it).

background = on/off
     Enable/disable going to background - the same as `-b' (which
     enables it).

backup_converted = on/off
     Enable/disable saving pre-converted files with the suffix `.orig'
     - the same as `-K' (which enables it).

base = STRING
     Consider relative URLs in URL input files forced to be interpreted
     as HTML as being relative to STRING - the same as `-B'.

cache = on/off
     When set to off, disallow server-caching.  See the `-C' option.

convert links = on/off
     Convert non-relative links locally.  The same as `-k'.

cut_dirs = N
     Ignore N remote directory components.

debug = on/off
     Debug mode, same as `-d'.

delete_after = on/off
     Delete after download - the same as `--delete-after'.

dir_prefix = STRING
     Top of directory tree - the same as `-P'.

dirstruct = on/off
     Turning dirstruct on or off - the same as `-x' or `-nd',
     respectively.

domains = STRING
     Same as `-D' (*Note Domain Acceptance::).

dot_bytes = N
     Specify the number of bytes "contained" in a dot, as seen
     throughout the retrieval (1024 by default).  You can postfix the
     value with `k' or `m', representing kilobytes and megabytes,
     respectively.  With dot settings you can tailor the dot retrieval
     to suit your needs, or you can use the predefined "styles" (*Note
     Download Options::).

dots_in_line = N
     Specify the number of dots that will be printed in each line
     throughout the retrieval (50 by default).

dot_spacing = N
     Specify the number of dots in a single cluster (10 by default).

dot_style = STRING
     Specify the dot retrieval "style", as with `--dot-style'.

exclude_directories = STRING
     Specify a comma-separated list of directories you wish to exclude
     from download - the same as `-X' (*Note Directory-Based Limits::).

exclude_domains = STRING
     Same as `--exclude-domains' (*Note Domain Acceptance::).

follow_ftp = on/off
     Follow FTP links from HTML documents - the same as `-f'.

follow_tags = STRING
     Only follow certain HTML tags when doing a recursive retrieval,
     just like `--follow-tags'.

force_html = on/off
     If set to on, force the input filename to be regarded as an HTML
     document - the same as `-F'.

ftp_proxy = STRING
     Use STRING as FTP proxy, instead of the one specified in
     environment.

glob = on/off
     Turn globbing on/off - the same as `-g'.

header = STRING
     Define an additional header, like `--header'.

http_passwd = STRING
     Set HTTP password.

http_proxy = STRING
     Use STRING as HTTP proxy, instead of the one specified in
     environment.

http_user = STRING
     Set HTTP user to STRING.

ignore_length = on/off
     When set to on, ignore `Content-Length' header; the same as
     `--ignore-length'.

ignore_tags = STRING
     Ignore certain HTML tags when doing a recursive retrieval, just
     like `-G' / `--ignore-tags'.

include_directories = STRING
     Specify a comma-separated list of directories you wish to follow
     when downloading - the same as `-I'.

input = STRING
     Read the URLs from STRING, like `-i'.

kill_longer = on/off
     Consider data longer than specified in content-length header as
     invalid (and retry getting it). The default behaviour is to save
     as much data as there is, provided there is more than or equal to
     the value in `Content-Length'.

logfile = STRING
     Set logfile - the same as `-o'.

login = STRING
     Your user name on the remote machine, for FTP.  Defaults to
     `anonymous'.

mirror = on/off
     Turn mirroring on/off.  The same as `-m'.

netrc = on/off
     Turn reading netrc on or off.

noclobber = on/off
     Same as `-nc'.

no_parent = on/off
     Disallow retrieving outside the directory hierarchy, like
     `--no-parent' (*Note Directory-Based Limits::).

no_proxy = STRING
     Use STRING as the comma-separated list of domains to avoid in
     proxy loading, instead of the one specified in environment.

output_document = STRING
     Set the output filename - the same as `-O'.

page_requisites = on/off
     Download all ancillary documents necessary for a single HTML page
     to display properly - the same as `-p'.

passive_ftp = on/off
     Set passive FTP - the same as `--passive-ftp'.

passwd = STRING
     Set your FTP password to PASSWORD.  Without this setting, the
     password defaults to `username@hostname.domainname'.

proxy_user = STRING
     Set proxy authentication user name to STRING, like `--proxy-user'.

proxy_passwd = STRING
     Set proxy authentication password to STRING, like `--proxy-passwd'.

quiet = on/off
     Quiet mode - the same as `-q'.

quota = QUOTA
     Specify the download quota, which is useful to put in the global
     `wgetrc'. When download quota is specified, Wget will stop
     retrieving after the download sum has become greater than quota.
     The quota can be specified in bytes (default), kbytes `k'
     appended) or mbytes (`m' appended).  Thus `quota = 5m' will set
     the quota to 5 mbytes. Note that the user's startup file overrides
     system settings.

reclevel = N
     Recursion level - the same as `-l'.

recursive = on/off
     Recursive on/off - the same as `-r'.

relative_only = on/off
     Follow only relative links - the same as `-L' (*Note Relative
     Links::).

remove_listing = on/off
     If set to on, remove FTP listings downloaded by Wget.  Setting it
     to off is the same as `-nr'.

retr_symlinks = on/off
     When set to on, retrieve symbolic links as if they were plain
     files; the same as `--retr-symlinks'.

robots = on/off
     Use (or not) `/robots.txt' file (*Note Robots::).  Be sure to know
     what you are doing before changing the default (which is `on').

server_response = on/off
     Choose whether or not to print the HTTP and FTP server responses -
     the same as `-S'.

simple_host_check = on/off
     Same as `-nh' (*Note Host Checking::).

span_hosts = on/off
     Same as `-H'.

timeout = N
     Set timeout value - the same as `-T'.

timestamping = on/off
     Turn timestamping on/off. The same as `-N' (*Note Time-Stamping::).

tries = N
     Set number of retries per URL - the same as `-t'.

use_proxy = on/off
     Turn proxy support on/off. The same as `-Y'.

verbose = on/off
     Turn verbose on/off - the same as `-v'/`-nv'.

wait = N
     Wait N seconds between retrievals - the same as `-w'.

waitretry = N
     Wait up to N seconds between retries of failed retrievals only -
     the same as `--waitretry'.  Note that this is turned on by default
     in the global `wgetrc'.

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File: wget.info,  Node: Sample Wgetrc,  Prev: Wgetrc Commands,  Up: Startup File

Sample Wgetrc
=============

   This is the sample initialization file, as given in the distribution.
It is divided in two section--one for global usage (suitable for global
startup file), and one for local usage (suitable for `$HOME/.wgetrc').
Be careful about the things you change.

   Note that almost all the lines are commented out.  For a command to
have any effect, you must remove the `#' character at the beginning of
its line.

     ###
     ### Sample Wget initialization file .wgetrc
     ###
     
     ## You can use this file to change the default behaviour of wget or to
     ## avoid having to type many many command-line options. This file does
     ## not contain a comprehensive list of commands -- look at the manual
     ## to find out what you can put into this file.
     ##
     ## Wget initialization file can reside in /usr/local/etc/wgetrc
     ## (global, for all users) or $HOME/.wgetrc (for a single user).
     ##
     ## To use the settings in this file, you will have to uncomment them,
     ## as well as change them, in most cases, as the values on the
     ## commented-out lines are the default values (e.g. "off").
     
     
     ##
     ## Global settings (useful for setting up in /usr/local/etc/wgetrc).
     ## Think well before you change them, since they may reduce wget's
     ## functionality, and make it behave contrary to the documentation:
     ##
     
     # You can set retrieve quota for beginners by specifying a value
     # optionally followed by 'K' (kilobytes) or 'M' (megabytes).  The
     # default quota is unlimited.
     #quota = inf
     
     # You can lower (or raise) the default number of retries when
     # downloading a file (default is 20).
     #tries = 20
     
     # Lowering the maximum depth of the recursive retrieval is handy to
     # prevent newbies from going too "deep" when they unwittingly start
     # the recursive retrieval.  The default is 5.
     #reclevel = 5
     
     # Many sites are behind firewalls that do not allow initiation of
     # connections from the outside.  On these sites you have to use the
     # `passive' feature of FTP.  If you are behind such a firewall, you
     # can turn this on to make Wget use passive FTP by default.
     #passive_ftp = off
     
     # The "wait" command below makes Wget wait between every connection.
     # If, instead, you want Wget to wait only between retries of failed
     # downloads, set waitretry to maximum number of seconds to wait (Wget
     # will use "linear backoff", waiting 1 second after the first failure
     # on a file, 2 seconds after the second failure, etc. up to this max).
     waitretry = 10
     
     
     ##
     ## Local settings (for a user to set in his $HOME/.wgetrc).  It is
     ## *highly* undesirable to put these settings in the global file, since
     ## they are potentially dangerous to "normal" users.
     ##
     ## Even when setting up your own ~/.wgetrc, you should know what you
     ## are doing before doing so.
     ##
     
     # Set this to on to use timestamping by default:
     #timestamping = off
     
     # It is a good idea to make Wget send your email address in a `From:'
     # header with your request (so that server administrators can contact
     # you in case of errors).  Wget does *not* send `From:' by default.
     #header = From: Your Name <username@site.domain>
     
     # You can set up other headers, like Accept-Language.  Accept-Language
     # is *not* sent by default.
     #header = Accept-Language: en
     
     # You can set the default proxy for Wget to use.  It will override the
     # value in the environment.
     #http_proxy = http://proxy.yoyodyne.com:18023/
     
     # If you do not want to use proxy at all, set this to off.
     #use_proxy = on
     
     # You can customize the retrieval outlook.  Valid options are default,
     # binary, mega and micro.
     #dot_style = default
     
     # Setting this to off makes Wget not download /robots.txt.  Be sure to
     # know *exactly* what /robots.txt is and how it is used before changing
     # the default!
     #robots = on
     
     # It can be useful to make Wget wait between connections.  Set this to
     # the number of seconds you want Wget to wait.
     #wait = 0
     
     # You can force creating directory structure, even if a single is being
     # retrieved, by setting this to on.
     #dirstruct = off
     
     # You can turn on recursive retrieving by default (don't do this if
     # you are not sure you know what it means) by setting this to on.
     #recursive = off
     
     # To always back up file X as X.orig before converting its links (due
     # to -k / --convert-links / convert_links = on having been specified),
     # set this variable to on:
     #backup_converted = off
     
     # To have Wget follow FTP links from HTML files by default, set this
     # to on:
     #follow_ftp = off

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File: wget.info,  Node: Examples,  Next: Various,  Prev: Startup File,  Up: Top

Examples
********

   The examples are classified into three sections, because of clarity.
The first section is a tutorial for beginners.  The second section
explains some of the more complex program features.  The third section
contains advice for mirror administrators, as well as even more complex
features (that some would call perverted).

* Menu:

* Simple Usage::        Simple, basic usage of the program.
* Advanced Usage::      Advanced techniques of usage.
* Guru Usage::          Mirroring and the hairy stuff.

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File: wget.info,  Node: Simple Usage,  Next: Advanced Usage,  Prev: Examples,  Up: Examples

Simple Usage
============

   * Say you want to download a URL.  Just type:

          wget http://fly.cc.fer.hr/

     The response will be something like:

          --13:30:45--  http://fly.cc.fer.hr:80/en/
                     => `index.html'
          Connecting to fly.cc.fer.hr:80... connected!
          HTTP request sent, awaiting response... 200 OK
          Length: 4,694 [text/html]
          
              0K -> ....                                                   [100%]
          
          13:30:46 (23.75 KB/s) - `index.html' saved [4694/4694]

   * But what will happen if the connection is slow, and the file is
     lengthy?  The connection will probably fail before the whole file
     is retrieved, more than once.  In this case, Wget will try getting
     the file until it either gets the whole of it, or exceeds the
     default number of retries (this being 20).  It is easy to change
     the number of tries to 45, to insure that the whole file will
     arrive safely:

          wget --tries=45 http://fly.cc.fer.hr/jpg/flyweb.jpg

   * Now let's leave Wget to work in the background, and write its
     progress to log file `log'.  It is tiring to type `--tries', so we
     shall use `-t'.

          wget -t 45 -o log http://fly.cc.fer.hr/jpg/flyweb.jpg &

     The ampersand at the end of the line makes sure that Wget works in
     the background.  To unlimit the number of retries, use `-t inf'.

   * The usage of FTP is as simple.  Wget will take care of login and
     password.

          $ wget ftp://gnjilux.cc.fer.hr/welcome.msg
          --10:08:47--  ftp://gnjilux.cc.fer.hr:21/welcome.msg
                     => `welcome.msg'
          Connecting to gnjilux.cc.fer.hr:21... connected!
          Logging in as anonymous ... Logged in!
          ==> TYPE I ... done.  ==> CWD not needed.
          ==> PORT ... done.    ==> RETR welcome.msg ... done.
          Length: 1,340 (unauthoritative)
          
              0K -> .                                                      [100%]
          
          10:08:48 (1.28 MB/s) - `welcome.msg' saved [1340]

   * If you specify a directory, Wget will retrieve the directory
     listing, parse it and convert it to HTML.  Try:

          wget ftp://prep.ai.mit.edu/pub/gnu/
          lynx index.html

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File: wget.info,  Node: Advanced Usage,  Next: Guru Usage,  Prev: Simple Usage,  Up: Examples

Advanced Usage
==============

   * You would like to read the list of URLs from a file?  Not a problem
     with that:

          wget -i file

     If you specify `-' as file name, the URLs will be read from
     standard input.

   * Create a mirror image of GNU WWW site (with the same directory
     structure the original has) with only one try per document, saving
     the log of the activities to `gnulog':

          wget -r -t1 http://www.gnu.ai.mit.edu/ -o gnulog

   * Retrieve the first layer of yahoo links:

          wget -r -l1 http://www.yahoo.com/

   * Retrieve the index.html of `www.lycos.com', showing the original
     server headers:

          wget -S http://www.lycos.com/

   * Save the server headers with the file:
          wget -s http://www.lycos.com/
          more index.html

   * Retrieve the first two levels of `wuarchive.wustl.edu', saving them
     to /tmp.

          wget -P/tmp -l2 ftp://wuarchive.wustl.edu/

   * You want to download all the GIFs from an HTTP directory.  `wget
     http://host/dir/*.gif' doesn't work, since HTTP retrieval does not
     support globbing.  In that case, use:

          wget -r -l1 --no-parent -A.gif http://host/dir/

     It is a bit of a kludge, but it works.  `-r -l1' means to retrieve
     recursively (*Note Recursive Retrieval::), with maximum depth of 1.
     `--no-parent' means that references to the parent directory are
     ignored (*Note Directory-Based Limits::), and `-A.gif' means to
     download only the GIF files.  `-A "*.gif"' would have worked too.

   * Suppose you were in the middle of downloading, when Wget was
     interrupted.  Now you do not want to clobber the files already
     present.  It would be:

          wget -nc -r http://www.gnu.ai.mit.edu/

   * If you want to encode your own username and password to HTTP or
     FTP, use the appropriate URL syntax (*Note URL Format::).

          wget ftp://hniksic:mypassword@jagor.srce.hr/.emacs

   * If you do not like the default retrieval visualization (1K dots
     with 10 dots per cluster and 50 dots per line), you can customize
     it through dot settings (*Note Wgetrc Commands::).  For example,
     many people like the "binary" style of retrieval, with 8K dots and
     512K lines:

          wget --dot-style=binary ftp://prep.ai.mit.edu/pub/gnu/README

     You can experiment with other styles, like:

          wget --dot-style=mega ftp://ftp.xemacs.org/pub/xemacs/xemacs-20.4/xemacs-20.4.tar.gz
          wget --dot-style=micro http://fly.cc.fer.hr/

     To make these settings permanent, put them in your `.wgetrc', as
     described before (*Note Sample Wgetrc::).

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File: wget.info,  Node: Guru Usage,  Prev: Advanced Usage,  Up: Examples

Guru Usage
==========

   * If you wish Wget to keep a mirror of a page (or FTP
     subdirectories), use `--mirror' (`-m'), which is the shorthand for
     `-r -N'.  You can put Wget in the crontab file asking it to
     recheck a site each Sunday:

          crontab
          0 0 * * 0 wget --mirror ftp://ftp.xemacs.org/pub/xemacs/ -o /home/me/weeklog

   * You may wish to do the same with someone's home page.  But you do
     not want to download all those images--you're only interested in
     HTML.

          wget --mirror -A.html http://www.w3.org/

   * But what about mirroring the hosts networkologically close to you?
     It seems so awfully slow because of all that DNS resolving.  Just
     use `-D' (*Note Domain Acceptance::).

          wget -rN -Dsrce.hr http://www.srce.hr/

     Now Wget will correctly find out that `regoc.srce.hr' is the same
     as `www.srce.hr', but will not even take into consideration the
     link to `www.mit.edu'.

   * You have a presentation and would like the dumb absolute links to
     be converted to relative?  Use `-k':

          wget -k -r URL

   * You would like the output documents to go to standard output
     instead of to files?  OK, but Wget will automatically shut up
     (turn on `--quiet') to prevent mixing of Wget output and the
     retrieved documents.

          wget -O - http://jagor.srce.hr/ http://www.srce.hr/

     You can also combine the two options and make weird pipelines to
     retrieve the documents from remote hotlists:

          wget -O - http://cool.list.com/ | wget --force-html -i -

\1f
File: wget.info,  Node: Various,  Next: Appendices,  Prev: Examples,  Up: Top

Various
*******

   This chapter contains all the stuff that could not fit anywhere else.

* Menu:

* Proxies::             Support for proxy servers
* Distribution::        Getting the latest version.
* Mailing List::        Wget mailing list for announcements and discussion.
* Reporting Bugs::      How and where to report bugs.
* Portability::         The systems Wget works on.
* Signals::             Signal-handling performed by Wget.

\1f
File: wget.info,  Node: Proxies,  Next: Distribution,  Prev: Various,  Up: Various

Proxies
=======

   "Proxies" are special-purpose HTTP servers designed to transfer data
from remote servers to local clients.  One typical use of proxies is
lightening network load for users behind a slow connection.  This is
achieved by channeling all HTTP and FTP requests through the proxy
which caches the transferred data.  When a cached resource is requested
again, proxy will return the data from cache.  Another use for proxies
is for companies that separate (for security reasons) their internal
networks from the rest of Internet.  In order to obtain information
from the Web, their users connect and retrieve remote data using an
authorized proxy.

   Wget supports proxies for both HTTP and FTP retrievals.  The
standard way to specify proxy location, which Wget recognizes, is using
the following environment variables:

`http_proxy'
     This variable should contain the URL of the proxy for HTTP
     connections.

`ftp_proxy'
     This variable should contain the URL of the proxy for HTTP
     connections.  It is quite common that HTTP_PROXY and FTP_PROXY are
     set to the same URL.

`no_proxy'
     This variable should contain a comma-separated list of domain
     extensions proxy should *not* be used for.  For instance, if the
     value of `no_proxy' is `.mit.edu', proxy will not be used to
     retrieve documents from MIT.

   In addition to the environment variables, proxy location and settings
may be specified from within Wget itself.

`-Y on/off'
`--proxy=on/off'
`proxy = on/off'
     This option may be used to turn the proxy support on or off.  Proxy
     support is on by default, provided that the appropriate environment
     variables are set.

`http_proxy = URL'
`ftp_proxy = URL'
`no_proxy = STRING'
     These startup file variables allow you to override the proxy
     settings specified by the environment.

   Some proxy servers require authorization to enable you to use them.
The authorization consists of "username" and "password", which must be
sent by Wget.  As with HTTP authorization, several authentication
schemes exist.  For proxy authorization only the `Basic' authentication
scheme is currently implemented.

   You may specify your username and password either through the proxy
URL or through the command-line options.  Assuming that the company's
proxy is located at `proxy.srce.hr' at port 8001, a proxy URL location
containing authorization data might look like this:

     http://hniksic:mypassword@proxy.company.com:8001/

   Alternatively, you may use the `proxy-user' and `proxy-password'
options, and the equivalent `.wgetrc' settings `proxy_user' and
`proxy_passwd' to set the proxy username and password.

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File: wget.info,  Node: Distribution,  Next: Mailing List,  Prev: Proxies,  Up: Various

Distribution
============

   Like all GNU utilities, the latest version of Wget can be found at
the master GNU archive site prep.ai.mit.edu, and its mirrors.  For
example, Wget 1.5.3+dev can be found at
`ftp://prep.ai.mit.edu/gnu/wget/wget-1.5.3+dev.tar.gz'

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File: wget.info,  Node: Mailing List,  Next: Reporting Bugs,  Prev: Distribution,  Up: Various

Mailing List
============

   Wget has its own mailing list at <wget@sunsite.auc.dk>, thanks to
Karsten Thygesen.  The mailing list is for discussion of Wget features
and web, reporting Wget bugs (those that you think may be of interest
to the public) and mailing announcements.  You are welcome to
subscribe.  The more people on the list, the better!

   To subscribe, send mail to <wget-subscribe@sunsite.auc.dk>.  the
magic word `subscribe' in the subject line.  Unsubscribe by mailing to
<wget-unsubscribe@sunsite.auc.dk>.

   The mailing list is archived at `http://fly.cc.fer.hr/archive/wget'.

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File: wget.info,  Node: Reporting Bugs,  Next: Portability,  Prev: Mailing List,  Up: Various

Reporting Bugs
==============

   You are welcome to send bug reports about GNU Wget to
<bug-wget@gnu.org>.  The bugs that you think are of the interest to the
public (i.e. more people should be informed about them) can be Cc-ed to
the mailing list at <wget@sunsite.auc.dk>.

   Before actually submitting a bug report, please try to follow a few
simple guidelines.

  1. Please try to ascertain that the behaviour you see really is a
     bug.  If Wget crashes, it's a bug.  If Wget does not behave as
     documented, it's a bug.  If things work strange, but you are not
     sure about the way they are supposed to work, it might well be a
     bug.

  2. Try to repeat the bug in as simple circumstances as possible.
     E.g. if Wget crashes on `wget -rLl0 -t5 -Y0 http://yoyodyne.com -o
     /tmp/log', you should try to see if it will crash with a simpler
     set of options.

     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, should you mail me the
     relevant parts of the file.

  3. Please start Wget with `-d' option and send the log (or the
     relevant parts of it).  If Wget was compiled without debug support,
     recompile it.  It is *much* easier to trace bugs with debug support
     on.

  4. If Wget has crashed, try to run it in a debugger, e.g. `gdb `which
     wget` core' and type `where' to get the backtrace.

  5. Find where the bug is, fix it and send me the patches. :-)

\1f
File: wget.info,  Node: Portability,  Next: Signals,  Prev: Reporting Bugs,  Up: Various

Portability
===========

   Since Wget uses GNU Autoconf for building and configuring, and avoids
using "special" ultra-mega-cool features of any particular Unix, it
should compile (and work) on all common Unix flavors.

   Various Wget versions have been compiled and tested under many kinds
of Unix systems, including Solaris, Linux, SunOS, OSF (aka Digital
Unix), Ultrix, *BSD, IRIX, and others; refer to the file `MACHINES' in
the distribution directory for a comprehensive list.  If you compile it
on an architecture not listed there, please let me know so I can update
it.

   Wget should also compile on the other Unix systems, not listed in
`MACHINES'.  If it doesn't, please let me know.

   Thanks to kind contributors, this version of Wget compiles and works
on Microsoft Windows 95 and Windows NT platforms.  It has been compiled
successfully using MS Visual C++ 4.0, Watcom, and Borland C compilers,
with Winsock as networking software.  Naturally, it is crippled of some
features available on Unix, but it should work as a substitute for
people stuck with Windows.  Note that the Windows port is *neither
tested nor maintained* by me--all questions and problems should be
reported to Wget mailing list at <wget@sunsite.auc.dk> where the
maintainers will look at them.

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File: wget.info,  Node: Signals,  Prev: Portability,  Up: Various

Signals
=======

   Since the purpose of Wget is background work, it catches the hangup
signal (`SIGHUP') and ignores it.  If the output was on standard
output, it will be redirected to a file named `wget-log'.  Otherwise,
`SIGHUP' is ignored.  This is convenient when you wish to redirect the
output of Wget after having started it.

     $ wget http://www.ifi.uio.no/~larsi/gnus.tar.gz &
     $ kill -HUP %%     # Redirect the output to wget-log

   Other than that, Wget will not try to interfere with signals in any
way. `C-c', `kill -TERM' and `kill -KILL' should kill it alike.

\1f
File: wget.info,  Node: Appendices,  Next: Copying,  Prev: Various,  Up: Top

Appendices
**********

   This chapter contains some references I consider useful, like the
Robots Exclusion Standard specification, as well as a list of
contributors to GNU Wget.

* Menu:

* Robots::                  Wget as a WWW robot.
* Security Considerations:: Security with Wget.
* Contributors::            People who helped.

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File: wget.info,  Node: Robots,  Next: Security Considerations,  Prev: Appendices,  Up: Appendices

Robots
======

   Since Wget is able to traverse the web, it counts as one of the Web
"robots".  Thus Wget understands "Robots Exclusion Standard"
(RES)--contents of `/robots.txt', used by server administrators to
shield parts of their systems from wanderings of Wget.

   Norobots support is turned on only when retrieving recursively, and
*never* for the first page.  Thus, you may issue:

     wget -r http://fly.cc.fer.hr/

   First the index of fly.cc.fer.hr will be downloaded.  If Wget finds
anything worth downloading on the same host, only *then* will it load
the robots, and decide whether or not to load the links after all.
`/robots.txt' is loaded only once per host.  Wget does not support the
robots `META' tag.

   The description of the norobots standard was written, and is
maintained by Martijn Koster <m.koster@webcrawler.com>.  With his
permission, I contribute a (slightly modified) TeXified version of the
RES.

* Menu:

* Introduction to RES::
* RES Format::
* User-Agent Field::
* Disallow Field::
* Norobots Examples::

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File: wget.info,  Node: Introduction to RES,  Next: RES Format,  Prev: Robots,  Up: Robots

Introduction to RES
-------------------

   "WWW Robots" (also called "wanderers" or "spiders") are programs
that traverse many pages in the World Wide Web by recursively
retrieving linked pages. For more information see the robots page.

   In 1993 and 1994 there have been occasions where robots have visited
WWW servers where they weren't welcome for various reasons. Sometimes
these reasons were robot specific, e.g. certain robots swamped servers
with rapid-fire requests, or retrieved the same files repeatedly. In
other situations robots traversed parts of WWW servers that weren't
suitable, e.g. very deep virtual trees, duplicated information,
temporary information, or cgi-scripts with side-effects (such as
voting).

   These incidents indicated the need for established mechanisms for
WWW servers to indicate to robots which parts of their server should
not be accessed. This standard addresses this need with an operational
solution.

   This document represents a consensus on 30 June 1994 on the robots
mailing list (`robots@webcrawler.com'), between the majority of robot
authors and other people with an interest in robots. It has also been
open for discussion on the Technical World Wide Web mailing list
(`www-talk@info.cern.ch'). This document is based on a previous working
draft under the same title.

   It is not an official standard backed by a standards body, or owned
by any commercial organization. It is not enforced by anybody, and there
no guarantee that all current and future robots will use it. Consider
it a common facility the majority of robot authors offer the WWW
community to protect WWW server against unwanted accesses by their
robots.

   The latest version of this document can be found at
`http://info.webcrawler.com/mak/projects/robots/norobots.html'.

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File: wget.info,  Node: RES Format,  Next: User-Agent Field,  Prev: Introduction to RES,  Up: Robots

RES Format
----------

   The format and semantics of the `/robots.txt' file are as follows:

   The file consists of one or more records separated by one or more
blank lines (terminated by `CR', `CR/NL', or `NL').  Each record
contains lines of the form:

     <field>:<optionalspace><value><optionalspace>

   The field name is case insensitive.

   Comments can be included in file using UNIX Bourne shell conventions:
the `#' character is used to indicate that preceding space (if any) and
the remainder of the line up to the line termination is discarded.
Lines containing only a comment are discarded completely, and therefore
do not indicate a record boundary.

   The record starts with one or more User-agent lines, followed by one
or more Disallow lines, as detailed below. Unrecognized headers are
ignored.

   The presence of an empty `/robots.txt' file has no explicit
associated semantics, it will be treated as if it was not present, i.e.
all robots will consider themselves welcome.

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File: wget.info,  Node: User-Agent Field,  Next: Disallow Field,  Prev: RES Format,  Up: Robots

User-Agent Field
----------------

   The value of this field is the name of the robot the record is
describing access policy for.

   If more than one User-agent field is present the record describes an
identical access policy for more than one robot.  At least one field
needs to be present per record.

   The robot should be liberal in interpreting this field. A case
insensitive substring match of the name without version information is
recommended.

   If the value is `*', the record describes the default access policy
for any robot that has not matched any of the other records. It is not
allowed to have multiple such records in the `/robots.txt' file.

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File: wget.info,  Node: Disallow Field,  Next: Norobots Examples,  Prev: User-Agent Field,  Up: Robots

Disallow Field
--------------

   The value of this field specifies a partial URL that is not to be
visited. This can be a full path, or a partial path; any URL that
starts with this value will not be retrieved. For example,
`Disallow: /help' disallows both `/help.html' and `/help/index.html',
whereas `Disallow: /help/' would disallow `/help/index.html' but allow
`/help.html'.

   Any empty value, indicates that all URLs can be retrieved. At least
one Disallow field needs to be present in a record.

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File: wget.info,  Node: Norobots Examples,  Prev: Disallow Field,  Up: Robots

Norobots Examples
-----------------

   The following example `/robots.txt' file specifies that no robots
should visit any URL starting with `/cyberworld/map/' or `/tmp/':

     # robots.txt for http://www.site.com/
     
     User-agent: *
     Disallow: /cyberworld/map/ # This is an infinite virtual URL space
     Disallow: /tmp/ # these will soon disappear

   This example `/robots.txt' file specifies that no robots should
visit any URL starting with `/cyberworld/map/', except the robot called
`cybermapper':

     # robots.txt for http://www.site.com/
     
     User-agent: *
     Disallow: /cyberworld/map/ # This is an infinite virtual URL space
     
     # Cybermapper knows where to go.
     User-agent: cybermapper
     Disallow:

   This example indicates that no robots should visit this site further:

     # go away
     User-agent: *
     Disallow: /

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File: wget.info,  Node: Security Considerations,  Next: Contributors,  Prev: Robots,  Up: Appendices

Security Considerations
=======================

   When using Wget, you must be aware that it sends unencrypted
passwords through the network, which may present a security problem.
Here are the main issues, and some solutions.

  1. The passwords on the command line are visible using `ps'.  If this
     is a problem, avoid putting passwords from the command line--e.g.
     you can use `.netrc' for this.

  2. Using the insecure "basic" authentication scheme, unencrypted
     passwords are transmitted through the network routers and gateways.

  3. The FTP passwords are also in no way encrypted.  There is no good
     solution for this at the moment.

  4. Although the "normal" output of Wget tries to hide the passwords,
     debugging logs show them, in all forms.  This problem is avoided by
     being careful when you send debug logs (yes, even when you send
     them to me).

\1f
File: wget.info,  Node: Contributors,  Prev: Security Considerations,  Up: Appendices

Contributors
============

   GNU Wget was written by Hrvoje Niksic <hniksic@iskon.hr>.  However,
its development could never have gone as far as it has, were it not for
the help of many people, either with bug reports, feature proposals,
patches, or letters saying "Thanks!".

   Special thanks goes to the following people (no particular order):

   * Karsten Thygesen--donated the mailing list and the initial FTP
     space.

   * Shawn McHorse--bug reports and patches.

   * Kaveh R. Ghazi--on-the-fly `ansi2knr'-ization.

   * Gordon Matzigkeit--`.netrc' support.

   * Zlatko Calusic, Tomislav Vujec and Drazen Kacar--feature
     suggestions and "philosophical" discussions.

   * Darko Budor--initial port to Windows.

   * Antonio Rosella--help and suggestions, plus the Italian
     translation.

   * Tomislav Petrovic, Mario Mikocevic--many bug reports and
     suggestions.

   * Francois Pinard--many thorough bug reports and discussions.

   * Karl Eichwalder--lots of help with internationalization and other
     things.

   * Junio Hamano--donated support for Opie and HTTP `Digest'
     authentication.

   * Brian Gough--a generous donation.

   The following people have provided patches, bug/build reports, useful
suggestions, beta testing services, fan mail and all the other things
that make maintenance so much fun:

   Tim Adam, Martin Baehr, Dieter Baron, Roger Beeman and the Gurus at
Cisco, Dan Berger, Mark Boyns, John Burden, Wanderlei Cavassin, Gilles
Cedoc, Tim Charron, Noel Cragg, Kristijan Conkas, Andrew Deryabin,
Damir Dzeko, Andrew Davison, Ulrich Drepper, Marc Duponcheel,
Aleksandar Erkalovic, Andy Eskilsson, Masashi Fujita, Howard Gayle,
Marcel Gerrits, Hans Grobler, Mathieu Guillaume, Dan Harkless, Heiko
Herold, Karl Heuer, HIROSE Masaaki, Gregor Hoffleit, Erik Magnus
Hulthen, Richard Huveneers, Simon Josefsson, Mario Juric, Goran
Kezunovic, Robert Kleine, Fila Kolodny, Alexander Kourakos, Martin
Kraemer, Simos KSenitellis, Hrvoje Lacko, Daniel S. Lewart, Dave Love,
Jordan Mendelson, Lin Zhe Min, Charlie Negyesi, Andrew Pollock, Steve
Pothier, Jan Prikryl, Marin Purgar, Keith Refson, Tobias Ringstrom,
Juan Jose Rodrigues, Edward J. Sabol, Heinz Salzmann, Robert Schmidt,
Toomas Soome, Tage Stabell-Kulo, Sven Sternberger, Markus Strasser,
Szakacsits Szabolcs, Mike Thomas, Russell Vincent, Charles G Waldman,
Douglas E. Wegscheid, Jasmin Zainul, Bojan Zdrnja, Kristijan Zimmer.

   Apologies to all who I accidentally left out, and many thanks to all
the subscribers of the Wget mailing list.