Additional Information
Lynx is usually 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 can also be used to display a file 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 o ther 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.). ToC
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
To exit Lynx use 'q' or CTRL-D. You will be asked whether you
really want to quit. Answering 'y' will exit and 'n' will return
you to the current document. ToC
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
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"
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 (the latter
must have its numlock key activated first though).
+-------+-------+-------+
| 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 v | link | | text 1| v 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 "histoy 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 and clear the history list.
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, and therefore
depends on how the Lynx program you are using was
configured. ToC
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
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
The Lynx Options Menu may be accessed by pressing the 'o' key.
The current Lynx Options Menu contains the following configurable
options.
E)ditor : vi
D)ISPLAY variable : aixtest.cc.ukans.edu:0.0
B)ookmark file : home_page
P)ersonal mail address : montulli@ukanaix.cc.ukans.edu
S)earching type : CASE INSENSITIVE
L)ocal execution links : ALWAYS OFF
V)I keys : ON
e(M)acs keys : OFF
K)eypad as arrows
or Numbered links : Numbers act as arrows
U)ser Mode : Novice
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.
- 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.
- Local execution links (**not currently active**)
- This option has three possible values. If set to ON, Lynx
will execute commands contained inside of links in any file. This
can be very dangerous so it is recommended that this option remain
ALWAYS OFF unless otherwise set by your system administrator.
Another value, FOR LOCAL FILES ONLY, allows execution only of
commands that are in files that reside on the local machine.
- VI keys
- If set to ON then the lowercase h,j,k, and l
keys will be mapped to left, down, up, and right, 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, 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.
ToC
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 not allowed. 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 subject, 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
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
The CTRL-R command will reload and rerender the file that you are
currently viewing. 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
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
create (insert) a bookmark file.
To save a bookmark to the document you wish to place in the
bookmark file press the 'a' key and you will be asked
do you wish to save this link in your current bookmark file? (y/n)'
Answer 'y' to save the link to the document you are currently
viewing in your bookmark page.
Use the 'v' command to view the list of bookmarks you have positioned.
While viewing the bookmark list you may select a bookmark as you would
any other link. ToC
- !
- When the '!' command is executed 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
usuall y 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.
ToC
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.
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
-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)
-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 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.
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
For a tutorial introduction to HTML see:
http://www.ncsa.uiuc.edu/demoweb/html-primer.html.
For reference information on HTML see:
http://info.cern.ch/hypertext/WWW/MarkUp/MarkUp.html
Lou Montulli
Michael Grobe
Stephen Ware
Academic Computing Services
The University of Kansas
Lawrence, Kansas 66045
ToC