Lynx Users Guide Version 2.3-FM

Lynx can be used to access information on the World Wide Web, 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.

Select a topic

• Viewing local files with Lynx
• Lynx online help
• Leaving Lynx
• Starting Lynx with a Remote File
• Starting Lynx with the the WWW_HOME environment variable.
• Navigating hypertext documents with Lynx
• Printing, Mailing, and Saving files to disk.
• Lynx searching commands
• Lynx options menu
• Comments and mailto: links
• USENET News posting
• Lynx and HTML Forms
• Viewing the HTML document source and editing documents
• Reloading files and refreshing the display
• Lynx bookmarks
• Jump command
• Directory Editing
• Other useful commands
• The Lynx command
• Lynx development history
• Additional Information

Viewing local files with Lynx

UNIX

lynx myfile

lynx /home/my-dir/myfile

VMS

lynx dua5:[my-directory]myfile

Lynx will also display files written in the HyperText Markup Language (HTML), if the file's name ends with the characters ".html". 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.

For example, these commands could be used to display files containing HTML hypertext:

UNIX

lynx myfile.html

lynx /home/my-dir/myfile.html

VMS

lynx dua5:[me]myfile.html

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.).

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 file to disk", which is disabled if Lynx is running in anonymous mode. Any number of additional download methods may be defined in the lynx.cfg file by the system administrator. Programs like kermit, zmodem and FTP are some possible options. ToC

Lynx online help

Leaving Lynx

Starting Lynx with a Remote File

PROTOCOL

identifies the communications protocol used by the server that will provide the file. As mentioned earlier, Lynx (and any WWW client) can interact with a variety of servers, each with its own protocol.

HOST

is the Internet address of the computer system on which the server is running, and

PATH and FILENAME

identify the directory path and file of interest.

HTTP (HyperText Transfer Protocol)

http://www.cc.ukans.edu/lynx_help/lynx_help_main.html

Gopher

gopher://gopher.micro.umn.edu/11/

FTP (File Transfer Protocol)

ftp://ftp2.cc.ukans.edu/pub/lynx/README

WAIS (Wide Area Information Service protocol)

wais://cnidr.org/directory-of-servers

lynx http://kufacts.cc.ukans.edu/cwis/kufacts_start.html

Starting Lynx with the the WWW_HOME environment variable.

UNIX

ksh

export WWW_HOME=http://info.cern.ch/default.html

csh

setenv WWW_HOME http://info.cern.ch/default.html

VMS

define "WWW_HOME" "http://info.cern.ch/default.html"

Navigating hypertext documents with Lynx

                                       +-------+-------+-------+
                                       | 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|
    +---------+---------+---------+    +-------+-------+-------+

The 'i' key presents an index of documents. The default index is usually a document pointing to servers around the world, but the index can be changed by the system administrator or on the command line using the -index switch, and therefore depends on how the Lynx program you are using was configured.

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. ToC

Printing, Mailing, and Saving files to disk.

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. Any number of additional print options may also be available as configured by your system administrator. ToC

Lynx searching commands

Lynx options menu

                      Options Menu

     E)ditor                    : emacs
     D)ISPLAY variable          : aixtest.cc.ukans.edu:0.0
     B)ookmark file             : home_page
     F)TP sort criteria         : By Filename
     P)ersonal mail address     : montulli@ukanaix.cc.ukans.edu
     S)earching type            : CASE INSENSITIVE
     C)haracter set             : ISO Latin 1
     V)I keys                   : OFF
     e(M)acs keys               : OFF
     K)eypad as arrows
          or Numbered links     : Numbers act as arrows
     l(I)st directory style	: Mixed style
     U)ser mode                 : Advanced
     L)ocal execution links     : Always off

For fields where you must choose from a list of choices, press any key to toggle the choices and 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:

Editor

The editor to be invoked when editing browsable files, and sending mail or comments. The full pathname of the editor command should be specified when possible.

DISPLAY variable

This option is only available on UNIX systems and is only relevant to X Window users. The DISPLAY variable is picked up automatically from the environment if it has been previously set.

Bookmark file

This is the filename and location of your personal bookmark file. The bookmark file allows frequently travelled links to be stored in a personal easy to access file. Using the 'a' command (see below) you may save any link into your bookmark file. If the path specified does not begin with a slash then the path will reference your home directory.

FTP sort criteria

This option allows you to specify how files will be sorted within FTP listings. The current options include "By Filename", "By Size", "By Type", and "By Date".

Personal mail address

This mail address will be used to help you send files to yourself and will be included as the From: address in any mail or comments that you send. It will also be sent as the From: field in all HTTP get requests.

Searching type

Searching type has two possible values: CASE INSENSITIVE (default) and CASE SENSITIVE. The searching type effects inter-document searches only, and determines whether searches for words within documents will be done in a case-sensitive or case-insensitive manner.

VI keys

If set to ON then the lowercase h,j,k, and l keys will be mapped to left, down, up, and right arrow, respectively.

Emacs keys

If set to ON then the CTRL-P, CTRL-N, CTRL-F, and CTRL-B keys will be mapped to up, down, right, and left arro arrow arroww, respectively.

Keypad as arrows or numbered links

This option gives the choice between navigating with the arrow keys or having every link numbered so that the links may be selected by numbers as well as using the arrow keys.

List directory style

Applies to Directory Editing. Files and directories can be presented in the following ways:

Mixed style

Files and directories are listed together in alphabetical order.

Directories first

Files and directories are separated into two alphabetical lists. Directories are listed first.

Files first

Files and directories are separated into two alphabetical lists. Files are listed first.

User Mode

There are three possible choices: Novice, Intermediate, and Advanced.

Novice

In Novice mode two lines of help are displayed at the bottom of the screen.

Intermediate

Intermediate mode turns off the help lines.

Advanced

Advanced mode displays the URL of the currently selected link at the bottom of the screen.

Local execution scripts or links

Local execution can be activated by the system administrator. If it has not been activated you will not see this option in the options menu. When a local execution script is encountered Lynx checks the users options to see whether the script can be executed. Users have the following options:

Always off

Local execution scripts will never be executed

For Local files only

Local execution scripts will only be executed if the script to be executed resides on the local machine, and is referenced by a URL that begins with "file://localhost"

Always on

All local exection scripts will be executed

If the users options permit the script to be executed Lynx will spawn a shell and run the script. If the script cannot be executed Lynx will show the script within the Lynx window and inform the user that the script is not allowed to be executed and will ask the user to check his/her options. ToC

Comments and mailto: links

Once you have decided to send a comment or have selected a "mailto:" link a new screen will appear showing you who you are sending the message to. 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' then the message will be sent, if you press 'n' the message will be deleted. ToC

USENET News posting

Reply to user@host

user@host will actually appear as the mail address of the person who posted the news article. Selecting the link will allow you to send a message to the person who wrote the message you are currently viewing. You will be given the option of including the original message in your reply.

Reply to newsgroup(s)

Selecting this link will allow you to post back to the newsgroup that you are currently reading and any newsgroups that the message may be cross-posted to. You will be given the option of including the original message in your reply. Once you have typed in your message the inews program will be called to post your message to your news host. ToC

Lynx and HTML Forms

An HTML Form provides for the use of buttons or to perform an action (such as submit), checkboxes and radio buttons to select options from a list, and fields for entering text.

Buttons:

Buttons are displayed in the same way that Lynx displays links in a document. To "push" the button press the RIGHT ARROW or RETURN key.

Checkboxes and Radio buttons

Checkboxes and radio buttons are displayed as parenthesis: (). When a box is checked or a button selected, an asterisk appears within the parenthesis: (*). To check a box or select a radio button press the RIGHT ARROW or RETURN key.

Selection Fields

Selection fields are displayed as brackets with the default option displayed between them: [default__]. To select an option press theRIGHT ARROW or RETURN key. A box with a border of asterisks will appear with the list of possible options listed within the box. Use the UP ARROW and DOWN ARROW keys to move the cursor between options and the RIGHT ARROW or RETURN key to select an option.

Text Entry Fields

Text entry fields are displayed as a row of underscores the length of the entry field: _______. You may enter text directly by typing at the keyboard. Use the BACKSPACE key to correct errors. If you input more text than the field can hold your input will be truncated. If you fill a text field the cursor will not move off the field but remain at the last field position.

NOTE:If you have a text input field selected you will not have access to any of the Lynx keystroke commands. Select a button or box when you want to use Lynx keystrokes.

Viewing the HTML document source and editing documents

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.

NOTE: When saving an HTML document it is important to name the document with a ".html" 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/FILENAME

lynx path/filename.html

Reloading files and refreshing the display

Lynx bookmarks

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):

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. ToC

Jump Command

Note to System Administrators: Read the "lynx.cfg" file on how to set up the jump command for your system and how to define shortcut names. ToC

Directory Editing

C)reate

Type 'c' to create a new file. New file will be empty.

D)ownload

Type 'd' to download selection using one of the options defined by your system administrator.

E)dit

Type 'e' to spawn the editor defined in options menu and load selected file for editing.

F)ull Menu

Type 'f' to show full menu of options available for selection. Menu may vary according to type of file selected and compression facilities available.

M)odify

Type 'm' to modify the name or location of file. Then type 'n' to rename the file or 'l' to move the file to a different location.

R)emove

Type 'r' to remove the selected file or directory.

T)ag

Type 't' to tag highlighted file. Further operations will be performed on tagged files instead of highlighted ones.

U)pload

Type 'u' to upload a file to the present directory. Upload methods are defined by your system administrator.

Other useful commands

!

When '!' is pressed your default shell will be spawned. When you quit or exit the shell you will return to Lynx. (Usually 'exit' under UNIX and 'logout' under VMS) This command is usually disabled for anonymous users.

g

The 'g' command allows any URL to be viewed. Pressing the 'g' command will bring up a prompt asking for a URL. Type in the URL that you wish to view.

=

The '=' command shows information about the current document and the currently selected link if there is one. The number of lines in the file, URL, title, owner, and type are shown.

z

Lynx supports completely interruptable I/O processes. Press the 'z' key at any time during a connect or transfer process and the process will be halted. If any data was transferred before the interrupt, it will be displayed. ToC

The Lynx command

lynx [options]

lynx [options] startup_file

startup_file

is the file that Lynx will load at start-up.

• If no file is specified, Lynx will use a default starting file and base directory determined during installation.
• If a specified file is local (i.e., not a URL) Lynx displays that file and uses the directory in which that file resides as the base directory.
• If a URL is specified, the file will be retrieved, and only the server base directory will be relevant to further accesses.

options

can be selected from the following list, where items in all-caps indicate that a substitution must be made.

-anonymous

used to specify the anonymous account.

-case

enable case-sensitive string searching.

-cache=NUMBER

set the NUMBER of documents cached in memory. The default is 10.

-cfg=FILENAME

specifies a Lynx configuration file other than the default lynx.cfg.

-display=DISPLAY

set the display variable for X rexeced programs.

-dump

dumps the formatted output of the default document or one specified on the command line to standard out. Under UNIX this can be used in the following way: lynx -dump http://info.cern.ch/default.html.

-editor=EDITOR

enable edit mode using the specified EDITOR. (vi, ed, emacs, etc.)

-emacskeys

enable emacs-like key movement.

-force_html

forces the first document to be interpreted as HTML.

-ftp

disable ftp access.

-help

print this Lynx command syntax usage message.

-index=URL

set the default index file to the specified URL

-noprint

disable print functions.

-nostatus

disable the retrieval status messages.

-print

enable print functions. (default)

-restrictions

allows a list of services to be disabled selectively and takes the following form: "lynx -restrictions=[option][,option][,option]..." This list is printed if no options are specified.

all

restricts all options.

bookmark

disallow changing the location of the bookmark file.

default

same as command line option -anonymous. Disables default services for anonymous users. Currently set to all restricted except for: inside_telnet, outside_telnet, inside_news, inside_ftp, outside_ftp, inside_rlogin, outside_rlogin, jump, mail and goto. Defaults are setable within userdefs.h.

disk_save

disallow saving binary files to disk in the download menu.

download

disallow downloaders in the download menu.

editor

disallow editing.

exec

disable execution scripts.

exec_frozen

disallow the user from changing the local execution option.

file_url

disallow using G)oto to go to file: URL's.

goto

disable the 'g' (goto) command.

inside_ftp

disallow ftps for people coming from inside your domain.

inside_news

disallow USENET news posting for people coming from inside you domain.

inside_rlogin

disallow rlogins for people coming from inside your domain.

inside_telnet

disallow telnets for people coming from inside your domain.

jump

disable the 'j' (jump) command.

mail

disable mailing feature.

news_post

disable USENET News posting.

options_save

disallow saving options in .lynxrc.

outside_ftp

disallow ftps for people coming from outside your domain.

outside_news

disallow USENET news posting for people coming from outside you domain.

outside_rlogin

disallow rlogins for people coming from outside your domain.

outside_telnet

disallow telnets for people coming from outside your domain.

print

disallow most print options.

shell

disallow shell escapes.

-rlogin

disable recognition of rlogin commands.

-show cursor

If enabled the cursor will not be hidden in the right hand corner but will instead be positioned at the start of the currently selected link. show cursor is the default for systems without FANCY_CURSES capabilities, and the default configuration can be changed in userdefs.h.

-source

works the same as dump but outputs HTML source instead of formatted text.

-telnet

disable recognition of telnet commands.

-term=TERM

tell Lynx what terminal type to assume its talking to. (This may be useful for remote execution, when, for example, Lynx connects to a remote TCP/IP port that starts a script that, in turn, starts another Lynx process.)

-trace

turns on WWW trace mode.

-vikeys

enable vi-like key movement.

-version

print version information

Lynx development history

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 capabilites offered in the curses environment.

At The University of Kansas, Lynx is used in several different ways to give users access to the campus wide information system. First, it is run on several local clients from a script named "kufacts" that points to the starting file located on a local server. Second, it runs whenever a user logs into an account called "kufacts" on a system named kufacts.cc.ukans.edu. Users without a local account may use this system to explore the KU CWIS and experiment with Lynx.

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. Now Jeff Porter, Craig Lavender and Ravikumar Kolli maintain Lynx. Special thanks goes to Foteos Macrides for his enthusiasm that has kept Lynx development going during the disruptive staff changes at the University of Kansas.

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 UN*X environment. Those versions also incorporated libraries from the UN*X 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.

Lynx is presently available via anonymous FTP from ftp2.cc.ukans.edu. Doslynx is also available from ftp2.cc.ukans.edu

ToC

Additional Information

For reference information on HTML see: http://info.cern.ch/hypertext/WWW/MarkUp/MarkUp.html