Lynx is a fully-featured World Wide Web (WWW) client for users running cursor-addressable, character-cell display devices (e.g., vt100 terminals, vt100 emulators running on PCs or Macs, or any other character-cell display). It will display Hypertext Markup Language (HTML) documents containing links to files on the local system, as well as files on remote systems running http, gopher, ftp, wais, nntp, finger, or cso/ph/qi servers, and services accessible via logins to telnet, tn3270 or rlogin accounts (see URL Schemes Supported by Lynx). Current versions of Lynx run on Unix, VMS, Windows3.x/9x/NT and later, 386DOS and OS/2 EMX.
Lynx can be used to access information on the WWW, or to build information systems intended primarily for local access. For example, Lynx has been used to build several Campus Wide Information Systems (CWIS). In addition, Lynx can be used to build systems isolated within a single LAN.
Online help is available while viewing any document. Press the “?” or “H” key (or the “h” key if vi-like key movement is not on) to see a list of help topics. See the section titled Navigating hypertext documents with Lynx for information on navigating through the help files.
In addition, a summary description of all the Lynx keystroke commands and their key bindings is available by pressing the “K” key (or the “k” key if vi-like key movement is not on).
If you want to recall recent status-line messages, you can do so by entering the “g” command, followed by “LYNXMESSAGES:”.
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Lynx can be started by entering the Lynx command along with the name of a file to display. For example these commands could all be used to display an arbitrary ASCII text or HTML file:
lynx filenamelynx /home/my-dir/filenamelynx ~/filenamelynx filenamelynx dua5:[my-directory]filenamelynx /dua5/my-directory/filenamelynx ~/filenamelynx sys$login:filenamelynx /sys$login/filenamelynx file:///filenamelynx filenamelynx c:/dir/filenamelynx //n/dir/filenameWhen executed, Lynx will clear the screen and display as much of the specified file as will fit on the screen. Pressing a down-arrow will bring up the next screen, and pressing an up-arrow will bring up the previous screen. If no file is specified at startup, a default file will be displayed, depending on settings e.g., in lynx.cfg.
Lynx will display local files written in the HyperText Markup Language (HTML), if the file's name ends with the characters .html, .htm, .shtml, .htmlx, .html3, or .ht3. HTML is a file format that allows users to create a file that contains (among other things) hypertext links to other files. Several files linked together may be described as a hypertext document. If the filename does not have one of the suffixes mapped by Lynx to HTML, the -force_html command line option can be included to force treatment of the file as hypertext.
When Lynx displays an HTML file, it shows links as "bold face" text, except for one link, which is shown as "highlighted" text. Whether "boldface" or "highlighted" text shows up as reverse video, boldface type, or a color change, etc. depends on the display device being used (and the way in which that device has been configured). Lynx has no control over the exact presentation of links.
The one link displayed as "highlighted" text is the currently "selected" link. Lynx will display the file associated with the selected link when a right-arrow or a Return key is pressed. To select a particular link, press the up-arrow or down-arrow keys until the desired link becomes "highlighted," and then press the right-arrow or Return key to view the linked information. Information included in the HTML file tells Lynx where to find the linked file and what kind of server will provide it (i.e., HTTP, Gopher, etc.).
Lynx renders HTML files and saves the rendition (and the source, if so configured in the lynx.cfg file) for initial display and should you select the link again. If you do select a link again and have reason to desire a new fetch and rendering of the file, use the NOCACHE command, normally mapped to “x” and “X”, instead of the right-arrow or Return key when positioned on the link. You also can force a new fetch and rendering of the currently displayed document via the RELOAD command, normally mapped to Control-R.
When a binary file is encountered Lynx will ask the user if he/she wishes to download the file or cancel. If the user selects “D” for download, Lynx will transfer the file into a temporary location and present the user with a list of options. The only default option is Save to disk, which is disabled if Lynx is running in anonymous mode. Additional download methods may be defined in the lynx.cfg file. Programs like kermit, zmodem and FTP are some possible options.
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To exit Lynx use the “q” command. You will be asked whether you really want to quit. Answering “y” will exit and “n” will return you to the current document. Use “Q” or Control-D to quit without verification.
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If you wish to view a remote file (that is, a file residing on some computer system other than the one upon which you are running Lynx) without first viewing a local file, you must identify that file by using a Uniform Resource Locator (URL). URLs take the general form:
PROTOCOL :// HOST / PATH
where
PROTOCOLHOSTPATHHere are some sample URLs.
http://invisible-island.net/lynx/gopher://gopher.micro.umn.edu/11/ftp://ftp2.cc.ukans.edu/pub/lynx/READMEwais://cnidr.org/directory-of-serverslynx
http://kufacts.cc.ukans.edu/cwis/kufacts_start.htmlLynx also will attempt to create a complete URL if you include
adequate portions of it in the startfile argument. For
example:
1234.6789.1234.6789.1234.6789.1234.6789.1234.6789.1234.6789.1234.6789.1234.6789
wfbr will be expanded to:
http://www.wfbr.edu/ and:
ftp.more.net/pub will be expanded to:
ftp://ftp.more.net/pub
See URL Schemes Supported by Lynx for more detailed information.
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You may also specify a starting file for Lynx using the WWW_HOME environment variable,
export WWW_HOME=http://www.w3.org/setenv WWW_HOME http://www.w3.org/define "WWW_HOME" "http://www.w3.org/"WWW_HOME=http://www.w3.org/ [or in
registry]Note that on VMS the double-quoting must be included to preserve casing.
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The process of moving within a hypertext web, selecting and displaying links is known as "navigation." With Lynx almost all navigation can be accomplished with the arrow keys and the numeric keypad.
+-------+-------+-------+
| TOP | /|\ | Page |
arrow keys | of | | | UP |
| text 7| | 8| 9|
+---------+ +-------+-------+-------+
| SELECT | | | | |
| prev /|\| | <--- | | ---> |
| link | | | 4| 5| 6|
+---------+---------+---------+ +-------+-------+-------+
| BACK | SELECT | DISPLAY | | END | | | Page |
|<-- prev | next | | sel. -->| | of | | | DOWN |
| doc. | link \|/| link | | text 1| \|/ 2| 3|
+---------+---------+---------+ +-------+-------+-------+
There are also a few other keyboard commands to aid in navigation. The Control and Function keys used for navigation within the current document are described in Scrolling and Other useful commands. Some additional commands depend on the fact that Lynx keeps a list of each link you visited to reach the current document, called the History Page, and a list of all links visited during the current Lynx session, called the Visited Links Page. The HISTORY keystroke command, normally mapped to Backspace or Delete, will show you the History Page of links leading to your access of the current document. Any of the previous documents shown in the list may be revisited by selecting them from the history screen. The VLINKS keystroke command, normally mapped to uppercase “V”, will show the Visited Links Page, and you similarly can select links in that list. The MAIN_MENU keystroke command, normally mapped to “m” and “M”, will take you back to the starting document unless you specified the -homepage=URL option at the command line. Also, the LIST and ADDRLIST keystroke commands, normally mapped to “l” and “A” respectively, will create a compact lists of all the links in the current document, and they can be selected via those lists.
The “i” key presents an index of documents. The default index offered contains many useful links, but can be changed in lynx.cfg or on the command line using the -index=URL switch.
If you choose a link to a server with active access authorization, Lynx will automatically prompt for a username and a password. If you give the correct information, you will then be served the requested information. Lynx will automatically send your username and password to the same server if it is needed again.
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Rendered HTML documents, and plain text files, may be printed using the “p” command while viewing the document. After pressing the “p” key a menu of Print Options will be displayed. The menu will vary according to several factors. First, some sites set up special accounts to let users run Lynx to access local information systems. Typically these accounts require no passwords and do not require users to identify themselves. As a result such accounts are called "anonymous" accounts, and their users are considered "anonymous" users. In most configurations, all Lynx users (including anonymous users) are able to mail files to themselves and print the entire file to the screen.
Additional print options are available for users who are using Lynx from their own accounts (that is, so-called "non-anonymous users"). In particular, the Save to a local file option allows you to save the document into a file on your disk space. Additional print options may also be available as configured in the lynx.cfg file.
Some options, such as Save to a local file, involve prompting for an output filename. All output filename entries are saved in a circular buffer, and any previous entries can be retrieved for re-use by pressing the up-arrow or down-arrow keys at the prompt.
Note that if you want exact copies of text files without any expansions of TAB characters to spaces you should use the Download options.
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When viewing HTML documents it is possible to retrieve and display the unrendered (i.e., the original HTML) source of the document by pressing the “\” (backslash) key. Lynx usually caches only the rendering of the document and does not keep the source (unless it is configured to do so in the lynx.cfg file), so to display the source unrendered, Lynx must reload it from the server or disk. When viewing unrendered documents you may print them as any normal document.
Selecting the Print to a local file option from the Print Menu, makes it possible to save the source of the document to disk so that you may have a local copy of the document source, but it is better to Download the source.
NOTE: When saving an HTML document it is important to name the document with a .html or .htm extension, if you want to read it with Lynx again later.
Lynx can allow users to edit documents that reside on the local system. To enable editing, documents must be referenced using a "file:" URL or by specifying a plain filename on the command line as in the following two examples:
lynx file://localhost/FULL/PATH/FILENAMElynx path/filename.htmlIn addition, the user must also specify an editor in the Options Menu so that Lynx knows which editor to use. If the file is specified correctly and an editor is defined, then you may edit documents by using the “e” command. When the “e” command is entered your specified editor is spawned to edit the file. After changes are completed, exit your editor and you will return to Lynx. Lynx will reload and render the file so that changes can be immediately examined.
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If the DOWNLOAD keystroke command (“d” or “D”) is used when positioned on a link for an HTML, plain text, or binary file, Lynx will transfer the file, without rendering, into a temporary location and present the user with a list of options, just as it does when a link for a binary file of a type for which no viewer has been mapped is activated.
There is a default Download option of Save to disk. This is disabled if Lynx is running in anonymous mode. Any number of download methods such as kermit and zmodem may be defined in addition to this default in the lynx.cfg file. Using the Save to disk option under the PRINT command after viewing the source of an HTML with the VIEW SOURCE (\) command will result in a file which differs from the original source in various ways such as tab characters expanded to spaces. Lynx formats the source presentation in this mode. On the other hand, if the DOWNLOAD command is used, the only change will be that Lynx optionally puts
<!--X-URL: http://www.site.foo/path/to/file.html -->
<BASE href="http://www.site.foo/path/to/file.html">
at the start of the file so that relative URLs in the document will still work. Even this modification can be prevented by setting PREPEND_BASE_TO_SOURCE:FALSE in lynx.cfg.
Some options, such as Save to disk, involve prompting for an output filename. All output filename entries are saved in a circular buffer, and any previous entries can be retrieved for re-use by pressing the up-arrow or down-arrow keys at the prompt.
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The RELOAD (Control-R) command will reload and re-render the file that you are currently viewing. The REFRESH (Control-L or Control-W) command will refresh or wipe the screen to remove or correct any errors that may be caused by operating system or other messages.
The NOCACHE (“x” or “X”) command can be used in lieu of ACTIVATE (Return or right-arrow) to request an uncached copy and new rendition for the current link, or resubmission of a FORM, if a cache from a previous request or submission exits. The request or submission will include Pragma: no-cache and Cache-Control: no-cache in its headers. Note that FORMs with POST content will be resubmitted regardless of whether the NOCACHE or ACTIVATE command is used (see Lynx and HTML Forms).
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Two commands activate searching in Lynx: “/” and “s”.
While viewing a normal document use the “/” command to find a word or phrase within the current document. The search type will depend on the search option setting in the Options Menu. The search options are case sensitive and case insensitive. These searches are entirely local to Lynx.
Some documents are designated index documents by virtue of an ISINDEX element in their HEAD section. These documents can be used to retrieve additional information based on searches using words or phrases submitted to an index server. The Lynx statusline will indicate that you are viewing such a document, and if so, the “s” key will invoke a statusline prompt to enter a query string. The prompt can be specified via a PROMPT attribute in the ISINDEX element. Otherwise, Lynx will use an internally configured prompt. The address for submitting the search can be specified via an HREF or ACTION attribute. Otherwise, Lynx will use the current document's URL and append your query string as a ?searchpart (see Supported URLs).
All search words or strings which you have entered during a Lynx session are saved in a circular buffer, and can be retrieved for re-use by pressing the up-arrow or down-arrow keys at the prompt for a search word or string. Also, you can use the “n”ext command to repeat a search with the last-entered search word or phrase, starting from the current position in the document. The word or phrase matches will be highlighted throughout the document, but such highlighting will not persist for new documents, or if the current document is reloaded. The search cycles to the top of the document if the word or phrase is not located below your current position.
Although HTML Forms have largely replaced
index documents for searches via http servers, they are still
useful for performing searches directly via WAIS or Gopher
servers in conjunction with the internal gateways for such
servers. For example, an HTML index document can act as a
cover page describing a WAIS database and how to
formulate query strings for searching it, and include an element
such as:
<ISINDEX PROMPT="Enter WAIS query:"
HREF="wais://net.bio.net/biologists-addresses">
for submitting a search of the Biologist's Addresses database directly to the net.bio.net WAIS server.
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The Lynx Options Menu may be accessed by pressing the “o” key. It allows you to change options at runtime, if you need to. Most changes are read from & saved to your .lynxrc file; those which are not are marked (!) in the form-based menu (as below). Many other options are stored in the lynx.cfg file.
Lynx supports two styles of Options Menu, key-based & form-based. The form-based menu shown below is an HTML file generated at runtime, in which the user fills in choices as in any ordinary HTML form.
Options Menu (Lynx Version 2.8.9dev.15)
Accept Changes - Reset Changes - Left Arrow cancels changes - HELP!
Save options to disk: [ ]
(options marked with (!) will not be saved)
General Preferences
User mode : [Advanced____]
Editor : vile______________________________________
Type of Search : [Case insensitive]
Security and Privacy
Cookies : [ask user__]
Invalid-Cookie Prompting (!) : [prompt normally___]
SSL Prompting (!) : [prompt normally___]
Keyboard Input
Keypad mode : [Numbers act as arrows_____________]
Emacs keys : [OFF]
VI keys : [OFF]
Line edit style : [Bash-like Bindings]
Display and Character Set
Use locale-based character set : [ON_]
Use HTML5 charset replacements(!): [OFF]
Display character set : [UNICODE (UTF-8)________________]
Assumed document character set(!): [iso-8859-1______]
Raw 8-bit : [OFF]
X Display : localhost:0.0_____________________________
Document Appearance
Show color : [ON____]
Color style (!) : [lynx.lss___________]
Default colors (!) : [ON_]
Show cursor : [OFF]
Underline links (!) : [OFF]
Show scrollbar : [ON_]
Popups for select fields : [ON_]
HTML error recovery : [strict (SortaSGML mode)]
Bad HTML messages (!) : [Warn, point to trace-file]
Show images : [ignore___]
Verbose images : [OFF__________]
Collapse BR tags (!) : [OFF_____]
Trim blank lines (!) : [trim-lines]
Headers Transferred to Remote Servers
Personal mail address : __________________________________________
Personal name for mail : __________________________________________
Password for anonymous ftp : __________________________________________
Preferred media type (!) : [Accept lynx's internal types]
Preferred encoding (!) : [All_____]
Preferred document character set : _________________________________
Preferred document language : en_______________________________
HTTP protocol (!) : [HTTP 1.0]
Send User-Agent header (!) : [X]
User-Agent header (!) : Lynx/2.8.8pre.2 libwww-FM/2.14 SSL-MM/1.4.
Listing and Accessing Files
Use Passive FTP (!) : [ON_]
FTP sort criteria : [By Date]
Local directory sort criteria : [Directories first]
Local directory sort order : [By Date_]
Show dot files : [OFF]
Pause when showing message (!) : [ON_]
Show transfer rate : [Show KiB/sec (2-digits), ETA__]
Special Files and Screens
Multi-bookmarks : [ADVANCED]
Review/edit Bookmarks files : Goto multi-bookmark menu
Auto Session (!) : [OFF]
Session file (!) : __________________________________________
Visited Pages : [By Last Visit Reversed_]
View the file lynx.cfg.
Accept Changes - Reset Changes - Left Arrow cancels changes
The key-based menu depends on key-strokes to identify options which the user wants to change. It is compiled into Lynx and is accessed by setting FORMS_OPTIONS to TRUE in lynx.cfg.
Options Menu (Lynx Version 2.8.9dev.15)
(E)ditor : emacs
(D)ISPLAY variable : aixtest.cc.ukans.edu:0.0
mu(L)ti-bookmarks: OFF B)ookmark file: lynx_bookmarks.html
(F)TP sort criteria : By Filename
(P)ersonal mail address : montulli@netscape.com
(S)earching type : CASE INSENSITIVE
preferred document lan(G)uage: en
preferred document c(H)arset : NONE
display (C)haracter set : Western (ISO-8859-1)
raw 8-bit or CJK m(O)de : ON show color (&) : OFF
(V)I keys: OFF e(M)acs keys: OFF sho(W) dot files: OFF
popups for selec(T) fields : ON show cursor (@) : OFF
(K)eypad mode : Numbers act as arrows
li(N)e edit style : Default Binding
l(I)st directory style : Mixed style
(U)ser mode : Advanced verbose images (!) : ON
user (A)gent : [User-Agent header]
local e(X)ecution links : FOR LOCAL FILES ONLY
An option can be changed by entering the capital letter or character in parentheses for the option you wish to change (e.g., “E” for Editor or “@” for show cursor). For fields where text must be entered, simply enter the text by typing on the keyboard. The Line Editor can be used to correct mistakes, and Control-U can be used to erase the line. When you are done entering a change press the Return key to get back to the Command? prompt.
For fields where you must choose one of two choices, press any key to toggle the choices and press the Return key to finish the change.
For fields where you potentially have more than two choices, popup windows may be evoked which function homologously to those for select fields in HTML Forms. The popup windows will be invoked only if you have popups for select fields set to ON (see below). Otherwise, your cursor will be positioned at the current choice, and you can press any key to cycle through the choices, then press the Return key to finish the change.
When you are done changing options use the “r” command to return to Lynx or the “>” command to save the options to a .lynxrc file and return to Lynx.
The following table describes the options available on the Options Menu:
Using the “a”dd bookmark link command (see Lynx bookmarks) you may save any link that does not have associated POST content into a bookmark file. All bookmark files must be in or under your account's home directory. If the location specified does not begin with a dot-slash (./), its presence will still be assumed, and referenced to the home directory.
When multi-bookmarks is STANDARD or ADVANCED, entering “B” will invoke a menu of up to 26 bookmark files (associated with the letters of the English alphabet), for editing their filenames and locations (filepath), and descriptions.
Lynx will create bookmark files, if they do not already exist, when you first “a”dd a bookmark link to them. However, if you've specified a subdirectory (e.g., ./BM/lynx_bookmarks.html), that subdirectory must already exist. Note that on VMS you should use the URL syntax for the filepath (e.g., not [.BM]lynx_bookmarks.html).
BR tags. If turned on, i.e.,
“collapse”, two or more concurrent BRs
will be collapsed into a single line break. Note that the valid
way to insert extra blank lines in HTML is via a
PRE block with only newlines in the block.Note: this has no direct effect on the line-editor's key bindings.
By
Filename", "By Size", "By
Type", and "By Date".BR-tags onto the previous line when
it happens to be empty as part of the Collapse BR tags
feature.Note: this has no effect on the line-editor's key bindings.
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At any time while viewing documents within Lynx, you may use the “c” command to send a mail message to the owner of the current document if the author of the document has specified ownership. (Note to authors: if you want to assign the ownership to your document, you need to add into HEAD section a LINK element with appropriate value for REV attribute. Two values are recognized: owner and made (these are case insensitive). For example,
<HEAD>
…
<LINK REV="made" HREF="mailto:user@somedomain.com">
…
</HEAD>
You may also add a TITLE attribute with, for example, the name of your page) If no ownership is specified then comments are disabled. Certain links called mailto: links will also allow you to send mail to other people. Using the mail features within Lynx is straightforward.
Once you have decided to send a comment or have selected a mailto: link a new screen will appear showing you to whom you are sending the message. Lynx will ask for your name, your e-mail address, and the subject of the message. If you have filled in the "personal mail address" field in the Options Menu, your e-mail address will be filled in automatically. After entering the above information, if you have an editor defined in the Options Menu and you are not an anonymous user then your specified editor will be spawned for you so that you can enter your message. If you do not have an editor defined or you are an anonymous user, a simple line mode input scheme will allow you to enter your message.
To finish sending the message, exit your spawned editor or, if you are using the simple line mode input scheme, type a “.” (period) on a line by itself. You will be asked a final time whether to send the message. If you press “y”, you will be prompted whether to append your signature file if one was defined in lynx.cfg and is accessible, and then the message will be sent, whereas if you press “n” the message will be deleted. Entering Control-G in response to any prompts also will cancel the mailing.
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While reading news articles with Lynx you should see a link that says Reply to: user@host and, if the nntp server from which you received the article supports posting from your site, a link that says Followup to: newsgroup(s)
See also RFC 977.
Bookmarks are entries in your bookmark file, which record the URL of a document you may want to return to easily, with a name of your choice to identify the document. To use bookmarks you must first have specified a name for your bookmark file in lynx.cfg or via the Options Menu.
To save a bookmark to the document you wish to place in the bookmark file press the “a” key and you will be asked:
Save D)ocument or L)ink to bookmark file or C)ancel? (d,l,c):
Answer “d” to save a link to the document you are currently viewing or “l” to save the link that is currently selected on the page. Selecting “c” will cancel without saving anything to your bookmark file.
A bookmark file will be created in conjunction with acting on the “a”dd command if it does not already exist. Otherwise, the link will be added to the bottom of the pre-existing bookmark file. You must have created a bookmark file via the “a”dd command before you can view it.
Use the “v” command to view the list of bookmarks you have saved. While viewing the bookmark list you may select a bookmark as you would any other link.
You can remove a link from the bookmark list by pressing the “r” key when positioned on that link. You also can use a standard text editor (e.g., via the “e”dit command while viewing a bookmark file, if an external editor has been defined via the Options menu) to delete or re-order links in the bookmark file, or to modify a link name by editing the content of the Anchor element for the link, but you should not change the format within the line for the link, consisting of an LI element followed by the Anchor element, nor cause the line to become wrapped to a second line. You similarly can change the link destination by editing the double-quoted value for the HREF attribute in the Anchor start tag, but you should not otherwise change the spacing within the start tag, nor add other attributes. You can add a new link while editing by copying an existing line for a link, to ensure the proper format, and then modifying its HREF value and Anchor content, but you should not add any other HTML markup to the bookmark file. If the format and spacing (other than the Anchor content or HREF value) within lines is changed or other HTML markup is added, the “a”dd and “r”emove commands may not work properly.
When multi-bookmarks (see Options Menu) is OFF, you will always view or add links to the default bookmark file. When it is STANDARD, a menu of up to 26 bookmark files will be invoked, and you select the bookmark file by entering its letter token. When it is ADVANCED, you will be prompted for the letter token, but can enter “=” to invoke the STANDARD selection menu, or RETURN for the default bookmark file. [ToC]
Similar to the bookmarks file is the jumps file: for an example, look in the samples subdirectory in the distribution package. To use the jumps command, create a jumps file with the same format as the sample file, but containing your own URLs & short-cut names. Once you have done that, typing “j” prompts you to enter a short-cut name, which will take you straight to the URL associated with the short-cut in the jumps file, much like using “g”. If you want to check which short-cuts are available, type “?” at the jump prompt for the full list.
You can set up a jumps file which makes Lynx prompt for parameters, e.g., as part of a search. Do this by putting a "%s" marker in the URL at each point where you want Lynx to fill in text. When you activate the corresponding jump, Lynx will prompt you for the parameters, one by one.
All jump short-cuts you have entered are saved in a circular
buffer in the same way as with “g” and
“/” (search):
previous entries can be retrieved with up-arrow or
down-arrow.
The jumps feature is especially useful for system administrators who have unsophisticated users to care for, but ordinary Lynx users who have a number of URLs they regularly visit while browsing may find using the jumps command speeds their movements.
For more advice how to set up the jumps command on your system and how to define short-cut names, read lynx.cfg .
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Lynx offers extended DIRED support on Unix (on VMS the more powerful CSwing program is recommended for character cell terminals, and can be offered via Lynx as a jump shortcut or execution link). When a local directory is accessed using a URL of the form file://localhost/path/, a new set of commands is available. With DIRED support you can create, edit, delete, copy, and move files on your local system. The commands available in DIRED mode are
C)reateD)ownloadE)ditF)ull MenuM)odifyR)emoveT)agU)pload[ToC]
A limited range of colors & mouse commands are available, if the user chooses: see lynx.cfg for details. [ToC]
A summary of all the keystroke commands and their key bindings can be invoked via the KEYMAP command, normally mapped to “k” and “K”. The following describes some of the most commonly used commands.
*****”. You also can submit
the document for validation via links in the online help menu.
If you are able to diagnose the problem, send a message about
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This section describes the Lynx Forms Interface. HTML gives document providers the ability to create on-line forms which may be filled out when the document is viewed. When a form is submitted the information on the form can be used to search a database or complete a survey.
An HTML Form provides for the use of buttons to perform an action (such as submit), checkboxes, radio buttons or popups to select options from a list, and fields for entering text.
NOTE: If you have a text input field selected you will not have access to most of the Lynx keystroke commands, because they are interpreted by the Line Editor as either text entries or editing commands. Select a button or box when you want to use Lynx keystrokes; or prefix your keystroke with ^V to temporarily escape from line editing.
Some flavors of UNIX, shells & terminal settings require that you enter ^V^Ve in order to start the external editor, as they also use ^V as default command-line quote key (called “lnext” in stty man pages and “stty -a” output); to avoid this, you can put “stty lnext undef” in your .cshrc file (or .profile or .bashrc, depending on what shell you use), or invoke Lynx with a wrapper script, e.g.
#!/bin/sh
stty lnext undef
$HOME/bin/lynx "$@"
stty lnext ^V
exit
NB when NOT in the Line Editor, ^V is by default bound to the command to switch between SortaSGML and TagSoup HTML parsing (i.e., SWITCH_DTD). To avoid confusion, either of these separate functions could be changed (mapped away) with a KEYMAP directive in lynx.cfg. For example,
KEYMAP:^V:DO_NOTHING
KEYMAP:#:SWITCH_DTD
would map SWITCH_DTD away from ^V to #, while leaving its default Line Editor function as a command escape in place. On the other hand,
KEYMAP:^V::NOP:1
KEYMAP:^_::LKCMD:1
would move ^V's Line Editor binding as command escape to ^_ for the first Line Edit style, letting ^V still act as SWITCH_DTD outside of text input fields.
(Textarea) Enter text. [ ..... ] (^Xe for editor).
An external editor has to be defined, for example in the Options Menu, before you can start using this function.
A key to invoke external TEXTAREA editing is normally
provided by the Line-Editor Key Bindings. A
KEYMAP directive in lynx.cfg can also be used to
make a different key invoke external editing; it will then
normally be necessary to prefix that key with ^V to
"escape" from line-editing. Two variants exist,
KEYMAP:e:EDITTEXTAREA
or
KEYMAP:e:DWIMEDIT
(the first is only functional for TEXTAREA editing, while the
second allows to use the same key for normal file editing as long as both functions do
not conflict).
Please see the note above for details about ^V behavior.
You can also use two other special TEXTAREA functions. Again, these are already bound to key sequences in the Line-Editor Bindings, by default ^Xg and ^Xi. You can use different keys by adding KEYMAP bindings to your lynx.cfg file, e.g. KEYMAP:$:GROWTEXTAREA
KEYMAP:#:INSERTFILE
With these bindings, (in a TEXTAREA only) ^V$ would add 5 lines to the TEXTAREA and ^V# would prompt for the name of an existing file to be inserted into the TEXTAREA (above the cursorline). An automatic variation of GROWTEXTAREA is normally compiled in, so that hitting Enter with the cursor on the last line adds a new line to the TEXTAREA, with the cursor on it.
If you have some single keys (or control keys) to spare
that you do not need for their normal purposes, you can
dedicate those keys to invoke the special functions (without
requiring a prefix key). For example, to use the ^E
key for the DWIMEDIT action, and the Insert key for
the INSERTFILE action, use
KEYMAP:^E:DWIMEDIT:PASS
KEYMAP:0x10C:INSERTFILE:PASS
(see lynx.cfg for other keystroke codes to use).
Note that the default bindings that use ^X as a prefix key may also work by substituting the Escape key for ^X. If your keyboard has a modifier (Meta) key that gets transmitted as an ESC prefix, for example Alt, you can then even use Alt-e instead of ^Xe, Alt-g instead of ^Xg, and so on. But this does not work reliably everywhere (it depends on the way Lynx is compiled, including which libraries are used, and behavior of the connection and terminal type).
In general, you can move around the form using the standard Lynx navigation keys. The up-arrow and down-arrow keys, respectively, select the previous or next field, box, or button. The TAB key selects the next field, box, or button.
To submit the form
press right-arrow or Return when positioned on
the form's submit button. If you've submitted the form previously
during the Lynx session, have not changed any of the form
content, and the METHOD was GET, Lynx will retrieve from
its cache what was returned from the previous submission. If you
wish to resubmit that form to the server with the same content as
previously, use the NOCACHE command (“x”)
when positioned on the submit button. The right-arrow
and Return keys also will invoke a no-cache resubmission
if the reply from a form submission included a META element with
a no-cache Pragma or Cache-Control directive:
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
or the server sent a "Pragma" or "Cache-Control" MIME header with a no-cache directive.
You also can use the DOWNLOAD (“d”) keystroke command when positioned on a form submit button if you wish to download the server's reply to the submission instead of having Lynx render and display it.
Forms which have POST as the METHOD, or a mailto: URL as the ACTION, are always resubmitted, even if the content has not changed, when you activate the submit button. Lynx normally will not resubmit a form which has POST as the METHOD if the document returned by the form has links which you activated, and then you go back via the PREV_DOC (left-arrow) command or via the History Page. Lynx can be compiled so that it resubmits the form in those cases as well, and the default can be changed via lynx.cfg, and toggled via the -resubmit_posts command line switch.
If the form has one text entry field and no other fields except, possibly, hidden INPUT fields not included in the display, then that field also serves as a submit button, and pressing right-arrow or Return on that field will invoke submission of the form. Be sure to use up-arrow, down-arrow or TAB to move off the text entry field, in such cases, if it is not your intention to submit the form (or to retrieve what was returned from an earlier submission if the content was not changed and the METHOD was GET).
Forms can have multiple submit buttons, if they have been assigned NAMEs in the markup. In such cases, information about which one of the buttons was used to submit the form is included in the form content.
Inlined images can be used as submit buttons in forms. If such buttons are assigned NAMEs in the markup, for graphic clients they can also serve as image maps, and the x,y coordinates of the graphic client's cursor position in the image when it was clicked are included in the form content. Since Lynx cannot inline the image, and the user could not have moved a cursor from the origin for the image, if no alternatives are made available in the markup Lynx sends a 0,0 coordinate pair in the form content. Document authors who use images as submit buttons, but have at least some concern for text clients and sight-challenged Webizens, should include VALUEs for the buttons in such markup. Lynx will then display the string assigned to the VALUE, as it would for a normal submit button. Some document authors incorrectly use an ALT instead of VALUE attribute for this purpose. Lynx "cooperates" by treating ALT as a synonym for VALUE when present in an INPUT tag with TYPE="image". If neither a VALUE nor an ALT attribute is present, Lynx displays "[IMAGE]-Submit" as the string for such buttons. If clickable images is set, the "[IMAGE]" portion of the string is a link for the image, and the "Submit" portion is the button for submitting the form. Otherwise, the entire string is treated as a submit button. If a VALUE or ALT attribute is present and clickable images is set, Lynx prepends "[IMAGE]" as a link for the image, followed by “-” and then the attribute's value as the displayed string for the submit button. Note that earlier versions of Lynx would send a name=value pair instead of a 0,0 coordinate pair if a TYPE="image" submit button was NAME-ed, had a VALUE attribute in the INPUT tag, and was used to submit the form. The script which analyzes the form content thus could be made aware whether the submission was by a user with a graphic client and had image loading turned on, or by a user who did not see the image nor make a conscious choice within it. However, requests that this be included in HTML specifications consistently have fallen on deaf ears, and thus Lynx now "fakes" a 0,0 coordinate pair whether or not a VALUE or ALT attribute is present in the INPUT tag. Ideally, the script which analyzes the submitted content will treat the 0,0 coordinate pair as an indicator that the user did not see the image and make a conscious choice within it.
Forms can have hidden INPUT fields, which are not displayed, but have NAMEs and VALUEs included in the content. These often are used to keep track of information across a series of related form submissions, but have the potential for including information about the user that might be considered to represent an invasion of privacy. NOTE, in this regard, that Lynx has implemented the HTML 3.0 DISABLED attribute for all of its form fields. These can be used to keep track of information across submissions, and to cast it unmodifiable in the current form, but keep the user aware that it will be included in the submission.
Forms most commonly are submitted to http servers with the content encoded as ENCTYPE="application/x-www-form-urlencoded" for analysis by a script, and Lynx treats that as the default if no ENCTYPE is specified in the FORM start tag. However, you can specify a mailto URL as the form's ACTION to have the form content sent, instead, to an email address. In such cases, you may wish to specify ENCTYPE="text/plain" in the form markup, so that the content will not be encoded, but remain readable as plain text.
Lynx also supports ENCTYPE="application/sgml-form-urlencoded" for which all reserved characters in the content will be hex escaped, as with application/x-www-form-urlencoded, but semicolons (“;”) instead of ampersands (“&”) will be used as the separator for name=value pairs in the form content. The use of semicolons is preferred for forms with the GET METHOD, because the GET METHOD causes the encoded form content to be appended as a ?searchpart for the form's ACTION, and if such URLs are used in text/html documents or bookmark files without conversion of the ampersands to SGML character references (& or &), their being followed by form field NAMEs which might correspond to SGML entities could lead to corruption of the intended URL.
NOTE, in this regard, that Lynx converts ampersands to & when creating bookmarks, and thus the bookmark links will not be vulnerable to such corruptions. Also NOTE that Lynx allows you to save links in your bookmark file for documents returned by forms with the GET METHOD, and which thus have the content appended as a ?searchpart, but not if the METHOD was POST, because the content would be lost and the link thus would be invalid.
Lynx supports ENCTYPE="multipart/form-data" for sending form content with name=value pairs encoded as multipart sections with individual MIME headers and boundaries. However, Lynx does not yet support INPUTs with TYPE="file" or TYPE="range" and will set the DISABLED attribute for all of the form's fields if any INPUTs with either of those two TYPEs are present, so that the form cannot be submitted. Otherwise, Lynx will submit the form with the multipart ENCTYPE.
A Content-Disposition: file; filename=name.suffix header can be used by CGI scripts to set the suggested filename offered by Lynx for “d”ownload and “p”rint menu options to save or mail the body returned by the script following submission of a FORM. Otherwise, Lynx uses the last symbolic element in the path for the FORM's ACTION, which is normally the script, itself, or a PATH_INFO field, and thus might be misleading. This also can be done via a META element in any document:
<META HTTP-EQUIV="Content-Disposition"
CONTENT="file; filename=name.suffix">
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As a text browser, Lynx does not display images as such -- you need to define a viewer in lynx.cfg: see there -- , but users can choose a number of ways of showing their presence.
There are 3 choices in lynx.cfg, with 2 corresponding keys:
MAKE_LINKS_FOR_ALL_IMAGES * IMAGE_TOGGLE
MAKE_PSEUDO_ALTS_FOR_INLINES [ INLINE_TOGGLE
VERBOSE_IMAGES no corresponding key
You can also use the Options Menu, as outlined below:
key lynx.cfg FM KM .lynxrc variable in source
* MAKE_LINKS_ Y N N clickable_images
[ MAKE_PSEUDO_ Y N N pseudo_inline_alts
VERBOSE_ Y Y Y verbose_img
FM = Form-based Menu ; KM = Key-based Menu ;
in .lynxrc , VERBOSE_IMAGES is called “verbose_images”:
the other two cannot be saved between sessions.
In the Form-based Menu, the 3-way “Show images” selection combines the effects of the “*” & “[” keys, as follows:
Ignore clickable_images = FALSE, pseudo_inline_alts = FALSE
As labels clickable_images = FALSE, pseudo_inline_alts = TRUE
As links clickable_images = TRUE, pseudo_inline_alts = unchanged
HTML includes markup for creating tables structured as arrays of cells aligned by columns and rows on the displayed page.
Lynx recognizes the TABLE element and all of its associated elements as described in RFC 1942 and will process any ID attributes in the start tags for handling as NAME-ed anchors, but does not create actual tables. Instead, it treats the TR start tag as a collapsible BR (line break), and inserts a collapsible space before the content of each TH and TD start tag. This generally makes all of the content of the table readable, preserves most of the intra-cell organization, and makes all of the links in the table accessible, but any information critically dependent on the column and row alignments intended for the table will be missed.
If inherently tabular data must be presented with Lynx, one can use PRE formatted content, or, if the table includes markup not allowed for PRE content, construct the table using HTML Tabs. An example table using TAB elements is included in the test subdirectory of the Lynx distribution.
Starting with version 2.8.3, Lynx renders some tables in tabular form. This tabular representation for simple tables (TRST) does not attempt to implement full support for any table model. Limitations are:
<P>,
<BR> etc. (although
<BR> may be ignored at the beginning of
the first cell or at the end of the last cell of a row).WIDTH, vertical alignment.Horizontal alignments (LEFT,
CENTER, RIGHT), COLSPAN,
and ROWSPAN are interpreted according to HTML
4.01. (ROWSPAN can only reserve empty space in
subsequent rows, because of the limitations above.) When TRST
fails because a table is not "simple" enough, the
representation falls back to the minimal handling described
earlier. Many (but, unfortunately, by no means all) tables that
represent inherently tabular material will thus be shown with
correct tabular formatting. Where table markup is used only for
layout purposes (containing whole blocks of text and list
within table cells) and not essential for understanding the
textual contents, it remains basically ignored. Some more
information on details is available in the file
README.TRST of the source distribution.
For tabular display of more complex tables, Lynx users can
make use of external scripts or programs. The normal Lynx
distribution currently does not provide such scripts, but they
can be written locally or downloaded from several sources. It is
suggested to use one of Lynx's facilities for invoking external
programs (see DOWNLOADER, PRINTER,
EXTERNAL, TRUSTED_LYNXCGI in lynx.cfg and lynxcgi: in
Supported URLs for information on various ways for
setting this up).
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Lynx implements the HTML 3.0 TAB element only when LEFT alignment is in effect. If the alignment is CENTER or RIGHT (JUSTIFY is not yet implemented in Lynx, and is treated as a synonym for LEFT), or if the TAB element indicates a position to the left of the current position on the screen, it is treated as a collapsible space. For purposes of implementing TAB, Lynx treats en units as half a character cell width when specified by the INDENT attribute, and rounds up for odd values (e.g., a value of either 5 or 6 will be treated as three spaces, each the width of a character cell). See the example table using TAB elements in the test subdirectory of the Lynx distribution as a model for using this functionality.
Note that this Users Guide and the Supported URLs page include TAB markup in a manner which degrades gracefully for WWW browsers which do not support it. Toggle to display of source and search for <tab to examine the use of TAB markup in these documents.
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Some implementations of HTML include markup, primarily designed for graphic clients, that is intended to create an array of simultaneously displayed, independently scrolling windows. Such windows have been termed frames.
Lynx recognizes the Netscape and Microsoft Explorer FRAME, FRAMESET, and NOFRAMES elements, but is not capable of windowing to create the intended positioning of frames. Instead, Lynx creates labeled links to the frame sources, typically positioned in the upper left corner of the display, and renders the NOFRAMES section. If the document provider has disregard for text clients and sight-challenged Webizens, and thus does not include substantive content in the NOFRAMES section or a link in it to a document suitable for text clients, you can usually guess from the labeling of the frame links which one has the substantive material (if there is any), or you can try each of those links to see if anything worthwhile is returned.
[ToC]
Some sites -- in ignorance of Lynx capabilities -- may tell you (for example) "to view this page you need Netscape Navigator". You can simply ignore such warnings and access the frames via the Lynx-generated links as above.
Some implementations of HTML markup include provisions for creating a non-scrolling window to be positioned at the top of each page, containing links with brief, descriptive link names, analogous to a Windows toolbar. Such windows have been termed banners.
Lynx recognizes and processes all of the HTML 3.0 REL attribute tokens in LINK elements for creating a banner, and a number of others which have subsequently been proposed. These banner tokens are Home, ToC, Contents, Index, Glossary, Copyright, Up, Next, Previous, Prev, Help, Search, Top, Origin, Navigator, Child, Disclaimer, Sibling, Parent, Author, Editor, Publisher, Trademark, Meta, URC, Hotlist, Begin, First, End, Last, Pointer, Translation, Definition, Chapter, Section, Subsection, Alternate, Documentation, Biblioentry, Bibliography, Start, Appendix, Bookmark and Banner. Any LINK elements with those tokens as the REL attribute value, and an HREF attribute value in the LINK, will invoke creation of a banner at the top of the first page, with the element's HREF as the link, and the token as the default link name. If a TITLE attribute is included in the LINK, its value will be used as the link name instead of the default. Bookmark and Banner are intended to be accompanied by a TITLE attribute, which in effect makes the namespace for REL banner tokens infinite.
If the special token Help is used as the REL value and no HREF is included in the LINK, Lynx will use it own HELPFILE URL for that link. For the special token Home without an HREF, Lynx will use the default STARTFILE (i.e., derived from the configuration files or the WWW_HOME environment variable, not the command line startfile if one was used). However, if a -homepage=URL was specified on the command line, its URL will be used as the HREF. For the special token Index without an HREF, Lynx will use the DEFAULT_INDEX_FILE derived from the configuration files, or if an -index=URL was specified on the command line, its URL will be used as the HREF.
Lynx does not waste screen real estate maintaining the banner at the top of every page, but the Lynx TOOLBAR keystroke command (“#”) will, any time it is pressed, position you on the banner so that any of its links can be activated, and pressing the left-arrow when in the banner will return you to where you were in the current document. The toolbar is indicated by a “#" preceding its first link when present on the screen, that is, when the first page of the document is being displayed. The availability of a toolbar is indicated by a “#” at the top, left-hand corner of the screen when the second or subsequent pages of the document are being displayed.
Lynx also recognizes the HTML 3.0 BANNER container element, and will create a banner based on its content if one has not already been created based on LINK elements. Lynx treats the Microsoft MARQUEE element as a synonym for BANNER (i.e., presenting its markup as a static banner, without any horizontal scrolling of its content). Lynx does not prefix the BANNER or MARQUEE content with a “#” because the content need not be only a series of links with brief, descriptive links names, but does add a “#” at the top, left-hand corner of the screen when the content is not being displayed, to indicate its accessibility via the TOOLBAR keystroke command.
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Lynx implements the HTML 3.0 FN element similarly to a named Anchor within the current document, and assumes that the footnotes will be positioned at the bottom of the document. However, in contrast to named Anchors, the FN container element is treated as a block (i.e., as if a new paragraph were indicated whether or not that is indicated in its content) with greater than normal left and right margins, and the block will begin with a FOOTNOTE: label. For example, if the document contains:
See the <A HREF="#fn1">footnote</A>.
activating that link will take you to the labeled rendering of:
<FN ID="fn1"><p>Lynx does not use popups for FN blocks.</p></FN>
i.e., position it at the top of the page. Then, upon reading the footnote, you can return to your previous position in the document by pressing the left-arrow key. The content of an FN element can be any HTML markup that is valid in the BODY of the document.
[ToC]
Lynx implements the HTML 3.0 NOTE
element (Admonishment) as a labeled block, i.e., as if a
new paragraph were indicated whether or not paragraphing markup
is included in its content, with greater than normal left and
right margins, and with the type of note indicated by an
emphasized label based on the value of its CLASS or ROLE
attribute. If no CLASS or ROLE attribute is included, the default
label NOTE: will be used. Lynx recognizes the values
caution and warning, for which, respectively,
the labels CAUTION: or WARNING: will be used.
The NOTE element can have an ID attribute, which will be treated
as a named Anchor, as for HTML
Footnotes, but the NOTE block need not be placed at the
bottom of the document. The content of a NOTE block can be any
HTML markup that is valid in the BODY of the document. This is an
example:
<NOTE CLASS="warning" ID="too-bad">
<p>The W3C vendors did not retain NOTE in the HTML 3.2 draft.</p>
</NOTE>
It will degrade gracefully for WWW browsers which do not support NOTE, except for recognition of the ID attribute as a named Anchor.
[ToC]
Lynx implements the HTML 3.0 list elements UL (Unordered List), OL (Ordered List), and DL (Definition List), and their associated attributes, and elements (LH, LI, DT, and DD) for the most part as described in that specification. The lists can be nested, yielding progressively greater indentation, up to six levels. The HTML 2.0 MENU and DIR elements both are treated as synonyms for UL with the PLAIN attribute (no bullets, see below). Note, thus, that neither DIR nor MENU yields a series of columns with 24-character spacing. A single nesting index is maintained, so that different types of List elements can be used for different levels within the nest. Also, the HTML 3.0 FIG, CAPTION and CREDIT elements are treated as valid within list blocks. They will be rendered with indentation appropriate for the current nesting depth, and the CAPTION or CREDIT elements will have a CAPTION: or CREDIT: label beginning the first line of their content. The content of any APPLET or OBJECT elements in the lists also will be indented appropriately for the current nesting depth, but those will not invoke line breaks unless indicated by their content, and it should not include markup which is inappropriate within the list.
Lynx also supports the TYPE attribute for OL elements, which can have values of 1 for Arabic numbers, I or i for uppercase or lowercase Roman numerals, or A or a for uppercase or lowercase letters, that increment for successive LI elements in the list block. The CONTINUE attribute can be used to continue the ordering from the preceding list block when the nesting depth is changed.
Lynx treats the OL attributes START and SEQNUM as synonyms for specifying the ordering value for the first LI element in the block. The values should be specified as Arabic numbers, but will be displayed as Arabic, Roman, or alphabetical depending on the TYPE for the block. The values can range from -29997 to the system's maximum positive integer for Arabic numbers. For Roman numerals, they can range from 1 (I or i) to 3000 (MMM or mmm.). For alphabetical orders, the values can range from 1 (A or a) to 18278 (ZZZ or zzz). If the CONTINUE attribute is used, you do not need to specify a START or SEQNUM attribute to extend the ordering from a previous block, and you can include a TYPE attribute to change among Arabic, Roman, or alphabetical ordering styles, or their casing, without disrupting the sequence. If you do not include a START, SEQNUM or CONTINUE attribute, the first LI element of each OL block will default to 1, and if you do not include a TYPE attribute, Lynx defaults to Arabic numbers.
For UL blocks without the PLAIN attribute, Lynx uses *, +, o, #, @ and - as bullets to indicate, progressively, the depth within the six nesting levels.
Lynx treats UL, OL, DIR, and MENU blocks as having the COMPACT attribute by default, i.e., single spaces between LH and LI elements within those blocks. For DL blocks, double spacing will be used to separate the DT and DD elements unless the COMPACT attribute has been specified.
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The HTML 3.0 and later specifications provide for two classes of quotation in HTML documents. Block quotes, designated by the BLOCKQUOTE element (or its abbreviated synonym BQ in HTML 3.0), have implied paragraph breaks preceding and following the start and end tags for the block. Character level quotes, designated by the Q element, in contrast are simply directives in the markup to insert an appropriate quotation mark.
Lynx renders block quotes with a greater than normal left and right indentation. Lynx does not support italics, and normally substitutes underlining, but does not underline block quotes so as not to obscure any explicit emphasis elements within the quotation. The BLOCKQUOTE or BQ block can include a CREDIT container element, whose content will be rendered as an implied new paragraph with a CREDIT: label at the beginning of its first line.
Lynx respects nested Q start and end tags, and will use ASCII double-quotes (") versus grave accent (`) and apostrophe ('), respectively, for even versus odd depths in the nest.
Any ID attributes in BLOCKQUOTE, BQ or Q elements can be the target of a hyperlink in the form URL#id. It is treated just like the NAME in Anchors.
[ToC]
Lynx has superior support for HTML 4.0/I18N internationalization issues. However, to see the characters other than 7bit properly you should set your display character set from Option Menu and save its value, this is a Frequently Asked Question. Fine-turning is also available from lynx.cfg
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HTML includes markup, designed primarily for graphic clients, that treats inlined images as maps, such that areas of the image within which a mouse cursor was positioned when the mouse was clicked can correspond to URLs which should be retrieved. The original implementations were based on the client sending an http server the x,y coordinates associated with the click, for handling by a script invoked by the server, and have been termed server-side-image-maps. Lynx has no rational way of coping with such a procedure, and thus simply sends a 0,0 coordinate pair, which some server scripts treat as an instruction to return a document suitable for a text client.
Newer HTML markup provides bases for the client to determine the URLs associated with areas in the image map, and/or for a text client to process alternative markup and allow the user to make choices based on textual information. These have been termed client-side-image-maps.
Lynx recognizes and processes the MAP container element and its AREA elements, and will create a menu of links for the HREF of each AREA when the link created for the IMG element with a USEMAP attribute is activated. The menu uses the ALT attributes of the AREA elements as the link names, or, if the document's author has disregard for text clients and sight-challenged Webizens, and thus did not include ALT attributes, Lynx uses the resolved URLs pointed to by the HREF attributes as the link names. Lynx uses the TITLE attribute of the IMG element, or the TITLE attribute of the MAP, if either was present in the markup, as the title and main header of the menu. Otherwise, it uses the ALT attribute of the IMG element. If neither TITLE nor ALT attributes were present in the markup, Lynx creates and uses a [USEMAP] pseudo-ALT. The MAPs need not be in the same document as the IMG elements. If not in the same document, Lynx will fetch the document which contains the referenced MAP, and locate it based on its NAME or ID attribute. All MAPs encountered in documents during a Lynx session are cached, so that they need not be retrieved repeatedly when referenced in different documents.
If the IMG element also indicates a server-side-image-map via an ISMAP attribute, Lynx normally will create a link for that as well, using an [ISMAP] pseudo-ALT (followed by a hyphen to indicate its association with the client-side-image-map) rather than ignoring it, and will submit a 0,0 coordinate pair if that link is activated. Although, the client-side-image-map may be more useful for a client such as Lynx, because all of the URLs associated with the image map can be accessed, and their nature indicated via ALT attributes, Lynx-friendly sites can map 0,0 such that the server returns a for-text-client document homologous to the content of FIG elements (see below). Inclusion of such a link for submissions to the server can be disabled by default via the configuration file (lynx.cfg), and the default can be toggled via the -ismap command line switch.
Lynx also recognizes the HTML 3.0 FIG and OVERLAY elements, and will handle them as intended for text clients. These are the ideal way to handle client-side-image-maps, because the FIG content provides complete alternative markup, rather than relying on the client to construct a relatively meager list of links with link names based on ALT strings.
The presently experimental OBJECT element encompasses much of the functionality of the FIG element for client-side-image-maps. Lynx will render and display the content of OBJECT elements which have the SHAPES attribute equivalently to its handling of FIG. Lynx also handles OBJECT elements with the USEMAP and/or ISMAP attributes equivalently to its handling of IMG elements with client-side-image-maps and/or server-side-image-maps.
[ToC]
HTML includes provision for passing instructions to clients via directives in META elements, and one such instruction, via the token Refresh, should invoke reloading of the document, fetched from a server with the same URL or a new URL, at a specified number of seconds following receipt of the current document. This procedure has been termed client-side-pull. An example of such an element is:
<META HTTP-EQUIV="Refresh" CONTENT="3; URL=http://host/path">
which instructs a client to fetch the indicated URL in 3 seconds after receiving the current document. If the URL= field is omitted, the URL defaults to that of the current document. A no-cache directive is implied when the Refresh if for the same URL.
Lynx recognizes and processes Refresh directives in META elements, but puts up a labeled link, typically in the upper left corner of the display, indicating the number of seconds intended before a refresh, and the URL for the refresh, instead of making the request automatically after the indicated number of seconds. This allows people using a braille interface any amount of time to examine the current document before activating the link for the next URL. In general, if the number of seconds indicated is short, the timing is not critical and you can activate the link whenever you like. If it is long (e.g., 60 seconds), a server process may be generating new documents or images at that interval, and you would be wasting bandwidth by activating the link at a shorter interval.
[ToC]
HTTP provides a means to carry state information across successive connections between a browser and an http server. Normally, http servers respond to each browser request without relating that request to previous or subsequent requests. Though the inclusion of INPUT fields with TYPE="hidden" can be used as a sort of state management by HTML Forms, a more general approach involves exchanges of MIME headers between the server and browser. When replying to a request, the server can send a Set-Cookie MIME header which contains information (cookies) relevant to the browser's request, and in subsequent requests the browser can send a Cookie MIME header with information derived from previously received cookies.
State Management via cookie exchanges originally was implemented by Netscape, and such cookies are now designated as Version 0. A more elaborate format for cookies, designated as Version 1, is being standardized by the IETF (Internet Engineering Task Force). Lynx supports both Version 0 and Version 1 cookie exchanges. This support can be disabled by default via the SET_COOKIES symbol in the compilation (userdefs.h) and/or run time (lynx.cfg) configuration files, and that default setting can be toggled via the -cookies command line switch. The SET_COOKIES symbol can be further modified by the ACCEPT_ALL_COOKIES mode. If ACCEPT_ALL_COOKIES is set TRUE, and SET_COOKIES is TRUE, Lynx will accept all cookies. Additionally, the cookies that are automatically accepted or rejected by Lynx can be further modified with the COOKIE_ACCEPT_DOMAINS and COOKIE_REJECT_DOMAINS options in your .lynxrc file, each of which is a comma-separated list of domains to perform the desired action. The domain listed in these options must be identical to the domain the cookie comes from, there is no wildcard matching. If a domain is specific in both COOKIE_ACCEPT_DOMAINS and COOKIE_REJECT_DOMAINS, rejection will take precedence.
When cookie support is enabled, Set-Cookie MIME headers received from an http server invoke confirmation prompts with possible replies of “Y”es or “N”o for acceptance of the cookie, “A”lways to accept the cookie and to allow all subsequent cookies from that domain (server's Fully Qualified Domain Name, or site-identifying portion of the FQDN) without further confirmation prompts, or ne“V”er to never allow cookies from that domain to be accepted (silently ignore its Set-Cookie MIME headers). All unexpired cookies are held in a hypothetical Cookie Jar which can be examined via the COOKIE_JAR keystroke command, normally mapped to Ctrl-K, for invoking the Cookie Jar Page. If Lynx has been compiled with the --enable-persistent-cookies flag, then unexpired cookies will be stored between sessions in the filename set with the COOKIE_FILE option in your .lynxrc.
A common use of cookies by http servers is simply to track the documents visited by individual users. Though this can be useful to the site's WebMaster for evaluating and improving the organization of links in the various documents of the site, if the user has configured Lynx to include a From MIME header with the user's email address in http requests, or has passed personal information to the server via a form submission, the tracking might be used to draw inferences, possibly incorrect, about that user, and may be considered by some as an invasion of privacy.
An example of worthwhile State Management via cookies is the setting of personal preferences, typically via a form submission to the site, which will then apply to all documents visited at that site.
If you accept cookies when accessing a site, but are given no indication about how they will be used in subsequent requests to that site, nor can infer how they will be used, you can Gobble (delete) the cookies and/or change the “allow” setting for its domain via the Cookie Jar Page.
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A list of documents which are in lynx's internal cache is accessible through hypothetical Cache Jar which can be examined via the CACHE_JAR keystroke command, normally mapped to Ctrl-X.
Entries in the Cache Jar are ordered from oldest (at the top) to newest. The user can easily access any document which is in the cache, especially those which may be soon removed due to configurable limits on the maximum number of cached documents, as well as the maxmimum amount of memory used by the cache.
The structure of Cache Jar is simple:
URL: label preceding the link.
Activating this link, lynx displays the corresponding cached
document.This feature can be enabled by default using the USE_CACHEJAR
symbol in the compilation (userdefs.h), as well as
enabled in lynx.cfg
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Lynx's current state (all information about the user's current activity with lynx) is called a session. Sessions are useful in particular if you are in the middle of exploring something on the web and you were forced to stop abruptly, losing any trace of your current work.
A session can be automatically restored as lynx starts after a clean exit. The session data is saved if lynx is invoked with the -session=FILENAME switch. The FILENAME is the name of the file where the session will be stored.
There are also switches for only restoring: -sessionin=FILENAME and for only saving: -sessionout=FILENAME sesions:
If you do not want to specify these options at each lynx startup, there is an option in lynx.cfg to enable automatic saving/restoring of session. To keep lynx startup/exit reasonable fast there is also an option in lynx.cfg specifying how much information about the current lynx session will be stored in file.
The syntax of the session file is simple. You can use a text editor to modify, add new entries, or remove URLs you no longer want.
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A summary of the Lynx command line options (switches) is returned to stdout if Lynx is invoked with the -help switch. A description of the options also should be available via the system man (Unix) pages or help (VMS) libraries. On Win32, typing lynx -help in a DOS window should display similarly. The basic syntax of the Lynx command line can be represented as one of the following:
Commandlynx [options]lynx [options] startfilewhere
startfileoptionsLynx provides many command-line options. Some options require a value (string, number or keyword). These are noted in the reference below. The other options set boolean values in the program. There are three types of boolean options: set, unset and toggle. If no option value is given, these have the obvious meaning: set (to true), unset (to false), or toggle (between true/false). For any of these, an explicit value can be given in different forms to allow for operating system constraints, e.g.,
-center:off
-center=off
-center-
Lynx recognizes "1", "+", "on" and "true" for true values, and "0", "-", "off" and "false" for false values. Other option-values are ignored.
The default boolean, number and string option values that are compiled into lynx are displayed in the help-message provided by lynx -help. Some of those may differ according to how lynx was built; see the help message itself for these values. The -help option is processed before any option, including those that control reading from the lynx.cfg file. Therefore runtime configuration values are not reflected in the help-message.
Capitalized items in the option summary indicate that a substitution must be made. These are the options:
--” (dash), then
Lynx expects to receive the arguments from stdin. This is
to allow for the potentially very long command line that
can be associated with the -get_data or
-post_data arguments (see below). It can also be
used to avoid having sensitive information in the invoking
command line (which would be visible to other processes on
most systems), especially when the -auth or
-pauth options are used. On VMS, the dash must be
encased in double-quotes ("-") and the keyboard input
terminated with Control-Z or the command file
input terminated by a line that begins with
“$”. On Unix, the keyboard input
terminator is Control-D. On Win32, [???].-accept_all_cookies-anonymous-assume_charset=MIMENAME-assume_local_charset=MIMENAME-assume_unrec_charset=MIMENAME-auth=ID:PW-base-bibp=URL-blink-book-buried_news-cache=NUMBER-center-case-cfg=FILENAME-child-child_relaxed-cmd_log=FILENAME-cmd_script=FILENAMEexitkeyDown Arrow. Printable
7-bit ASCII codes are given as-is, and hexadecimal
values represent other 8-bit codes.set-color-connect_timeout=N-cookie_file=FILENAME-cookie_save_file=FILENAME-cookie_file is used.-cookies-core-crawl-curses_pads-debug_partial-display=DISPLAY-display_charset=MIMEname-dont_wrap_pre-dump-editor=EDITOR-emacskeys-enable_scrollback-error_file=FILENAME-exec-fileversions-find_leaks-force_empty_hrefless_a-force_html-force_secure-forms_options-from-ftp-get_data-head-help-hiddenlinks=optionmergelistonly-dump or from the
Print menu, but appear separately at the end
of those lists. This is the default behavior.ignore-historical-homepage=URLURL for the
“m”ain menu command.-image_links-ismap-index=URL-justify-link=NUMBER-localhost-locexec-lss=FILENAME-mime_header-minimal-nested_tables-newschunksize=NUMBER-newsmaxchunk=NUMBER-nobold-nobrowse-nocc-nocolor-noexec-nofilereferer-nolist-nolog-nomargins-nomore-nonrestarting_sigwinch-nopause-noprint-noredir-noreferer-noreverse-nosocks-nostatus-notitle-nounderline-number_fields-number_links-partial-partial_thres=NUMBER-pauth=ID:PW-popup-post_data-preparsed-prettysrc-print-pseudo_inlines-raw-realm-reload-restrictions-resubmit_posts-rlogin-scrollbar-scrollbar_arrow-selective-session=FILENAME-sessionin=FILENAME-sessionout=FILENAME-short_url-show_cursor-show_rate-soft_dquotes-source
lynx -source . >foo.html
generates HTML source listing the files in the current directory. Each file is marked by an HREF relative to the parent directory. Add a trailing slash to make the HREF's relative to the current directory:
lynx -source ./ >foo.html
-stack_dump-startfile_ok-stderr-dump or
-source, Lynx normally does
not display alert (error) messages that you see on the
screen in the status line. Use the
-stderr option to tell Lynx
to write these messages to the standard error.-stdin-syslog=text-syslog-urls-tagsoup-telnet-term=TERM-timeout=N-tlog-tna-trace-trace_mask=value-traversal-trim_input_fields-underscore-use_mouse-useragent=STRING-validate-verbose-version-vikeys-wdebug-width=NUMBER-with_backspacesman does).No options are required, nor is a startfile argument required. White space can be used in place of equal sign separators (“=”) appearing in the option list above. It can not be used in place of the equal signs in forms like "-option=on" and "-option=off" for simple switches and toggles, for which "-option" alone (without a value) is valid.
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Lynx uses certain environment variables and sets a few of them. Please visit a separate page for this rather technical information.
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Lynx has several levels of customization: from the Options Menu (accessible on-line, and possibly stored in your local .lynxrc file), via command-line switches on startup (mainly for batch processing). The most important and numerous default settings are stored in the Lynx configuration file lynx.cfg.
If you are on a UNIX system you should have appropriate permissions to make changes there or ask your system administrator to modify lynx.cfg for your needs. This file provides default settings for all accounts on your system. It may be copied to your shell account and included with -cfg command line switch or via an environment variable LYNX_CFG (if you have shell access). Starting with version 2.8.1 Lynx has an include facility so you can load the system-wide configuration file and easily add one or more settings from your local add-on configuration file. It is really cool to read lynx.cfg with its comments for hundreds of options, most of them commented out because they are built-in defaults. You may visit an index of options: by category or by alphabet.
To view your current configuration derived from lynx.cfg and any included configuration files, press “g” and type in “lynxcfg:”. If you are using the forms-based Options Menu, you may press “o” for the Options Menu and follow the “Check your lynx.cfg's link near the bottom.
However, for those who have a restricted account many Lynx features may be disabled by the system administrator, you probably will not see your lynx.cfg.
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Lynx grew out of efforts to build a campus-wide information system at The University of Kansas. The earliest versions of Lynx provided a user-friendly, distributed hypertext interface for users connected to multiuser (Unix and VMS) systems via curses-oriented display devices. A custom hypertext format was developed to support hypertext links to local files and files on remote Gopher servers. Using Gopher servers for distributed file service allowed information providers to publish information from a wide variety of platforms (including Unix, VMS, VM/CMS and Macintosh). In addition, Lynx became the most user-friendly Gopher client, although that was only an ancillary capability.
This distributed approach let providers retain complete control over their information, but it made communication between users and providers somewhat more difficult. Following the lead of Neal Erdwien, of Kansas State University, the Lynx hypertext format was extended to include links for including ownership information with each file. This information made it possible for users running Lynx clients to send comments and suggestions via e-mail to the providers.
This early version of Lynx was also augmented to support hypertext links to programs running on remote systems. It included the ability to open a Telnet connection, as well as the ability to start programs via rexec, inetd, or by direct socket connects. These capabilities were included to allow users to access databases or custom program interfaces.
A subsequent version of Lynx incorporated the World Wide Web libraries to allow access to the full list of WWW servers, along with the option to build hypertext documents in HTML, rather than the native Lynx format. HTML has become far more widely used, and the native format has been phased out. With the addition of the WWW libraries, Lynx became a fully-featured WWW client, limited only by the display capabilities offered in the curses environment.
Lynx was designed by Lou Montulli, Charles Rezac and Michael Grobe of Academic Computing Services at The University of Kansas. Lynx was implemented by Lou Montulli and maintained by Garrett Arch Blythe and Craig Lavender.
Foteos Macrides and members of the lynx-dev list have developed and supported
Lynx since release of v2.3 in May 1994.
The Lynx2-3FM code set was released as v2.4 in June 1995.
The Lynx2-4FM code set was released as v2.5 in May 1996.
The Lynx2-5FM code set was released as v2.6 in September
1996.
The Lynx2-6FM code set was released as v2.7 in February 1997.
The v2-7FM code set was released as v2.7.1 in April 1997.
The v2-7-1FM code set was released as v2.7.2 in January 1998.
The 2.7.1 development set was released as v2.8 in March 1998.
The 2.8 development set was released as v2.8.1 in October
1998.
The 2.8.1 development set was released as v2.8.2 in June
1999.
The 2.8.2 development set was released as v2.8.3 in April
2000.
The 2.8.3 development set was released as v2.8.4 in July
2001.
The 2.8.4 development set was released as v2.8.5 in February
2004.
The 2.8.5 development set was released as v2.8.6 in October
2006.
The 2.8.6 development set was released as v2.8.7 in July
2009.
The 2.8.7 development set was released as v2.8.8 in February
2014.
Since early 1997, the Lynx code has expanded into autoconfigure and PC versions. The branching of the Lynx source base from a single source into two sources (FM/Foteos Macrides and ac/autoconfigure) should be considered a healthy synergism among groups of computer professionals acting in their spare time out of a common goal.
Lynx has incorporated code from a variety of sources along the way. The earliest versions of Lynx included code from Earl Fogel of Computing Services at the University of Saskatchewan, who implemented HYPERREZ in the Unix environment. Those versions also incorporated libraries from the Unix Gopher clients developed at the University of Minnesota, and the later versions of Lynx rely on the WWW client library code developed by Tim Berners-Lee (and others) and the WWW community.
Contributors have generally been acknowledged in the CHANGES file. Earlier CHANGES file can be found in the docs/ subdirectory of this distribution.
Information on obtaining the most current version of Lynx is available at the current distribution page.
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