.TH MOTHRA 1
.SH NAME
mothra \- retrieve World-Wide Web files
.SH SYNOPSIS
.B mothra
[
.I url
]
.SH DESCRIPTION
.I Mothra
retrieves and displays files from the World-Wide Web,
by name or through hypertext links.
Web names, called URLs, have a peculiar syntax:
.IP
.EX
http://netlib.att.com/netlib/1127/www/1127.html
http://akebono.stanford.edu:80/yahoo/
http://www.teleport.com/~crowell/
file:/sys/lib/mothra/help.html
file:html2.elements.html#ADDRESS
ftp://ftp.gmd.de/music/scores/harrington/Harrington.readme
gopher://gopher.bev.net/11/BevBus/King.Video
.EE
.PP
The part up to the first colon gives the protocol for
retrieving the file.
.BR http: ,
Hyper-Text Transfer
Protocol, is the usual way of accessing web files.
.B file:
names a file in the local file system.
.B ftp:
and
.B gopher:
are standard Internet services.
.PD
.PP
.B //
begins the Internet address of the server where the file resides.
The address may contain a colon and a TCP port
number, which overrides the 
default port number for the service.  Next comes a
file name.  Finally, the file name may be followed by
.B #
and a string giving a label within the file where the
display should begin.
.PP
.I Mothra
starts with the
.I url
given on the command line, defaulting to
the environment variable
.BR $url ,
and finally to
.BR file:/sys/lib/mothra/start.html .
.PP
The display contains the last message from
.I mothra,
a box where typed commands appear,
a scrollable list of previously visited files,
the title and URL of the current file,
and the scrollable text of the current file.
.PP
Button 1 selects and displays a file, either from the list
of previously visited pages or from a link (indicated
by underlined text or a boxed image) in the
current file.  Button 2 shows the URL of a file,
but does not retrieve or display it.
Button 3 pops up a menu of commands:
.TF save\ back
.TP
.B save back
Place a link to the current file in a `back list'
for future reference.
.TP
.B get back
Retrieve and display the back list.
.TP
.B fix cmap
Adjust the display's color map so that images will
have correct colors.
.TP
.B exit
Ask for confirmation and quit.
.PD
.PP
The typed commands are:
.TF save\ back
.TP
.BI g " url
Get the page with the given URL.
.TP
.BI s " file
Save the current file in the given
.I file.
.TP
.B q
Quit.
.TP
.B ?
.TP
.B h
Get help.
.PD
.PP
When
.I mothra
retrieves a file that is not an
HTML document (for example a GIF or JPEG
image), it will start up an appropriate viewer, for example
.B fb/9v
(see
.IR 9v (9.1))
for image files.
.PP
To deal with sites that use `basic authentication', make a file
.BR $home/lib/mothra/insecurity,
containing lines of the form
.IP
.IR security-domain <tab> account-name\fL:\fPpassword
.LP
The method of registering an account varies with
site and may not reveal the
.I security-domain
string.  To learn the name,
summon a protected page and get the name from
the resulting error message.
.SH FILES
.B /sys/lib/mothra/*
.br
.B $home/lib/mothra/back.html 
the back list
.br
.B $home/lib/mothra/mothra.url
log of visited URLs
.br
.B $home/lib/mothra/mothra.err
log of error messages, including HTML syntax errors
.br
.B $home/lib/mothra/insecurity
authentication data
.SH SOURCE
.B /sys/src/cmd/mothra
.SH BUGS
.B ftp:
URLs are not supported.
.br
Files are saved in the form received,
not in the form suggested by the name in an
.B s
command.
.br
.I Mothra
is distributed in a preliminary state; it has more than its share of bugs.