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LYNX USERS GUIDE VERSION 2.3
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
"curses-oriented" display). It will display hypertext markup language
(HTML) hypertext documents containing links to files residing on the
local system, as well as files residing on remote systems running
Gopher, HTTP, FTP, WAIS, and NNTP servers. Current versions of Lynx
run on UNIX and VMS. A DOS version is in development.
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
* Other useful commands
* The Lynx command
* Lynx development history
* Additional Information
Viewing local files with Lynx
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 file.
UNIX
lynx myfile
lynx /home/my-dir/myfile
VMS
lynx dua5:[my-directory]myfile
When 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. (The default is configured by the system
administrator when the command is installed.)
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
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.).
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
Online help is available while viewing any document. Press the '?' or
'H' key to see a list of help topics. See the section titled
'Navigating hypertext documents with Lynx' for information on
navigating through the help files. ToC
Leaving Lynx
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 CTRL-D to quit without verification. ToC
Starting Lynx with a Remote File
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). URL's take the general form:
PROTOCOL :// HOST / PATH / FILENAME
where
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.
Here are some sample URL's.
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
A URL may be specified to Lynx on the command line, as in:
lynx http://kufacts.cc.ukans.edu/cwis/start_kufacts.html
ToC
Starting Lynx with the the WWW_HOME environment variable.
You may also specify a starting file for Lynx using 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
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.
Some of these commands depend on the fact that Lynx keeps a list of
each file you visit called the "history list". The "backspace" or
"delete" key will show you the whole history list. Any of the
documents shown in the list may be revisited by selecting them from
the history screen. The 'm' key command will take you back to the
starting document.
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.
Documents may be printed using the 'p' command. 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. Any number of additional
print options may also be available as configured by your system
administrator. ToC
Lynx searching commands
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 (see below). The search options are case
sensitive and case insensitive. Some documents are designated "index
documents". These documents can be searched to retrieve additional
information from an index server. The "s" key allows searching of
index documents. ToC
Lynx options menu
The Lynx Options Menu may be accessed by pressing the 'o' key. The
current Lynx Options Menu contains the following configurable options.
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
U)ser mode : Advanced
L)ocal execution links : Always off
An option can be changed by entering the capital letter of the option
you want to change (i.e. 'E' for Editor). For fields where text must
be entered, simply enter the text by typing on the keyboard. The
Backspace and Delete keys can be used to correct mistakes, and CTRL-U
can be used to erase the whole 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 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.
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
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. 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 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
While reading news articles with Lynx you should see a link that says
"Reply to user@host" and a link that says "Reply to newsgroup(s)"
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
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 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.
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.
You can move around the form using the standard Lynx navigation keys.
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.
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
When viewing HTML documents it is possible to view the unrendered
(i.e., the original HTML) source of the document by pressing the '\'
(backslash) key. The document will be reloaded from the server or disk
and displayed on the screen unrendered. 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.
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
In 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. ToC
Reloading files and refreshing the display
The CTRL-R command will reload and rerender the file that you are
currently viewing. CTRL-L or CTRL-W will refresh or wipe the screen to
remove or correct any errors that may be caused by operating system or
other messages. ToC
Lynx bookmarks
It is often useful to place a bookmark to aid in returning quickly to
a document. To use the bookmark feature you must first use the Options
Menu to specify a bookmark filename.
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 saveing anything to your bookmark file.
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
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
The basic syntax of the Lynx command can be represented as one of the
following:
lynx [options]
lynx [options] pathname
lynx [options] URL
where
pathname
is the name of an ASCII text file or an HTML file that enters a
hypertext network.
+ 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
-exec
enable local program execution
-locexec
enable local program execution from local files only
-noexec
disable local program execution (default)
-help
print this Lynx command syntax usage message
-index=URL
set the default index file to the specified URL
-noprint
disable print functions
-print
enable print functions (default)
-restrictions
allows a list of services to be disabled selectively and
takes the following form: "lynx -restrictions=[default],
[all], [inside_telnet], [outside_telnet], [shell],
[editor], [bookmark], [option_save], [print], [file_url],
[download], [exec]"
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, and goto. Defaults are setable
within userdefs.h.
download
disallow saving binary files to disk in the
download menu.
editor
disallow editing.
exec
disable execution scripts.
file_url
disallow using G)oto to go to file: URL's.
goto
disable the 'g' (goto) command.
inside_telnet
disallow telnets for people coming from inside your
domain.
options_save
disallow saving options in .lynxrc.
outside_telnet
disallow telnets for people coming from outside
your domain.
print
disallow most print options.
shell
disallow shell escapes.
-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 embedded telnet commands
completely.
-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
No options are required, nor is a starting file required. White space
may be substituted for any equal sign (=) appearing in the option list
above. ToC
Lynx development history
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 (UN*X 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 UN*X, 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 is
being 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 is now maintained by Garrett Arch
Blythe.
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.
ToC
Additional Information
For a tutorial introduction to HTML see:
http://www.ncsa.uiuc.edu/demoweb/html-primer.html.
For a quick reference guide to HTML see:
http://kuhttp.cc.ukans.edu/lynx_help/HTML_quick.html
For reference information on HTML see:
http://info.cern.ch/hypertext/WWW/MarkUp/MarkUp.html
Garrett Blythe
Lou Montulli
Michael Grobe
Stephen Ware
Academic Computing Services
The University of Kansas
Lawrence, Kansas 66045
ToC