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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
<html> <head>
<title>Manweb Reference Documentation</title>
</head>
<body>
<h1>manweb</h1>

<h2>NAME</h2>
manweb - browse netpbm (and other) documentation

<h2 id="synopsis">SYNOPSIS</h2>

<b>manweb</b> <b>-help</b>
<p>
<b>manweb</b>
[<b>-config=<i>configfile</i></b>]
[<i>topic</i> [ <i>subtopic</i> ... ] ]

<h2 id="examples">EXAMPLES</h2>

<pre>
manweb
</pre>
This gets a master index of documentation.
<pre>
manweb netpbm
</pre>
This gets the main documentation page for the Netpbm package, with hyperlinks
to the rest of the documentation.
<pre>
manweb netpbm pngtopam
</pre>
This goes directly to the documentation page for the Pngtopam program in
the Netpbm package.
<pre>
manweb pngtopam
</pre>
This also goes directly to the documentation page for the Pngtopam program in
the Netpbm package, if that's what would run in response to a <b>pngtopam</b>
shell command (your <b>PATH</b> environment variable is involved).
<pre>
manweb 3 fopen
</pre>
This gets the traditional man page for the fopen() subroutine using
<b>man</b>.
<pre>
manweb cp
</pre>
This gets the GNU Info manual for the <b>cp</b> program, using <b>info</b>.


<h2 id="description">DESCRIPTION</h2>

<p><b>manweb</b> displays reference documentation via quick shell
commands.  It is a replacement for the well-known <b>man</b>.

<h2>Differences Between Man and Manweb</h2>

<p><b>manweb</b>'s advantages over <b>man</b> are:

<ul>
  <li>
       You can access documentation that is on the worldwide web instead of
       having locally installed copies.  This saves installation work and gets
       you more current documentation.
       </li>
  <li>
       Documentation can be in HTML, which is more widely known, more widely
       useful, and more expressive than the nroff/troff format used by
       <b>man</b>.
       </li>
  <li>
       <b>manweb</b> puts your topics in a tree for multilevel documentation.
       <b>man</b> is intended for a single level of documentation.  For
       example, you can have a man page for each shell command, but not for
       the subcommands of a shell command.  And you cannot properly have
       man pages for the members of multiple subroutine libraries.
       </li>
  <li>
       Documentation can be hyperlinked.
</ul>

<p>Web servers need not be involved -- the documentation can be in local
files.  Graphics need not be involved -- the <b>lynx</b> browser works fine
in the same kind of terminals in which <b>man</b> works.

<p><b>manweb</b> finds the documentation you specify and calls a web
browser of your choice to display it.  The documentation <b>manweb</b>
finds can be either an HTML file on your system, in which case,
<b>manweb</b> gives a <b>file:</b> URL to your browser, or an explicit
URL.  That explicit URL might be an <b>http:</b> URL referring to an
HTML file on a web server somewhere, or anything else your browser
understands.

<p>If <b>manweb</b> finds neither an HTML file nor a URL, but your parameters
look like they could mean something to <b>man</b>, <b>manweb</b> calls
<b>man</b>.  Therefore, you can use a single command to access the vast
body of traditional man pages, plus any newer <b>manweb</b> documentation.
You can make "man" a shell alias of "manweb".

<p><b>manweb</b> finds Info documentation as well.  It looks for the
topic you specify as an Info topic after looking for HTML and URL
documentation and before running <b>man</b>.  If <b>manweb</b> finds a
corresponding Info topic, it runs the program <b>info</b> on it.  Info
is the documentation system that the GNU project invented to, among
other things, replace traditional Unix man pages.  However, HTML and the
Worldwide Web were invented shortly afterward, so Info fizzled.  But there
is still a lot of GNU software that is documented as Info topics.

<h3>How Manweb Finds Documentation</h3>

<p><b>manweb</b> passes a URL to a web browser.  This section tells
how your <b>manweb</b> invocation parameters turn into that URL.

<p><b>manweb</b>'s search starts in the "web directory" directory.
That's either the value of the <b>webdir</b> keyword in your
<b>manweb</b> configuration file, or the default <b>/usr/man/web</b>.

<p>Your invocation parameters form a "topic chain."  Going from left to right,
the first parameter is the main topic, the 2nd is a subtopic of the main
topic, and so on.

<p>Let's look at the simple case where you specify exactly one parameter --
a main topic.  We'll call it <i>maintopic</i> and look at 4 ways
<b>manweb</b> might find it:

<ol>
  <li>
       <p>If <b>manweb</b> finds a file named <i>maintopic</i><b>.html</b>
       in the web directory, the URL <b>manweb</b> passes to the
       browser is just a <b>file:</b> URL that specifies that .html
       file.
       </li>
  <li>
       <p>If there's no .html file, but there is a file named
       <i>maintopic</i><b>.url</b>, the contents of the first line of
       that .url file is what <b>manweb</b> passes to the browser.  It
       doesn't interpret the contents at all.  If it's garbage, the
       browser chokes on it.
       </li>
  <li>       
       <p>If there's neither a .html nor a .url file, but there is a
       directory named <i>maintopic</i>, <b>manweb</b> looks in the
       directory for a file named <i>index.html</i>.  If there is one,
       <b>manweb</b> passes a <b>file:</b> URL specifying that
       index.html file to the browser.  If there's no
       <i>index.html</i>, <b>manweb</b> uses a <b>file:</b> URL that
       specifies the directory itself.
       </li>
  <li>
       <p>If <b>manweb</b> doesn't find documentation in any of the
       above ways, it searches your executable search path (as defined
       by your <b>PATH</b> environment variable) for a program named
       <i>maintopic</i>.  If it finds one, it looks in the directory
       that contains the program for a file named <b>doc.url</b>.  If
       it finds one, it appends <i>maintopic</i><b>.html</b> to the
       first line of the file and passes that to the browser.  Unless 
       the first line does <em>not</em> end with a slash -- in that 
       case, <b>manweb</b> passes the first line of the file unmodified
       to the browser.
       </ol>

<p>It gets a little more interesting when you have subtopics.  Looking
at each of the 4 cases above:

<ol>
  <li>
       Where <i>maintopic</i><b>.html</b> exists, subtopics are invalid.
       You get a warning message and the subtopics are ignored.
       </li>
  <li>
       Where there's no .html file but <i>maintopic</i><b>.url</b> exists,
       <b>manweb</b> appends the subtopic chain to the URL it gets from the
       .url file as in the following example:  .url file contains
       <b>http://acme.com/productxyz/</b> and subtopics are
       <b>create</b> and
       <b>database</b>.  The URL <b>manweb</b> passes to the browser is
       <b>http://acme.com/productxyz/create/database.html</b>.

       <p><b>manweb</b> doesn't check that this kind of appendage makes
       any sense for the URL in question, except that if the URL in the
       .url file doesn't end with a slash (<b>/</b>), <b>manweb</b>
       issues a warning and doesn't append anything (ignores the subtopics).
  <li>
       Where there's neither a .html file nor a .url file, but there's a
       <i>maintopic</i> directory, <b>manweb</b> recurses into that
       directory and begins a whole new search using the first subtopic
       as the main topic and the rest of the subtopics as subtopics of that.
  <li>
       When there are subtopics, the <b>PATH</b> thing doesn't make sense,
       so <b>manweb</b> doesn't do it.
</ol>

If you give subtopics, the <b>PATH</b> thing described above for one
topic doesn't apply.

<p>If you give no parameters at all, <b>manweb</b> generates a URL for the
web directory itself as described above for subdirectories.

<p>The above is simplified by the assumption of a single web
directory.  In reality, the <b>webdir</b> keyword in the configuration
file can specify a chain of web directories.  <b>manweb</b> searches
each one in turn, doing all the kinds of searches in each web directory
before moving on to the next one.

<h3>The Configuration File</h3>

<p>The default location of the <b>manweb</b> configuration file is
<b>/etc/manweb.conf</b>.  But you can override this with the environment
variable <b>MANWEB_CONF_FILE</b>, and override that with the
<b>-config</b> invocation option.

<p>Lines starting with "#" are comments and are ignored, as are blank lines.

<p>All other lines have the format <i>keyword</i>=<i>value</i>.  The
keywords defined are:
<dl>
  <dt>webdir
  <dd>
       A colon-delimited sequence of directories to search for
       documentation as described above.  If you
       don't specify this, the default is <b>/usr/man/web</b> alone.
  <dt>browser
  <dd>
       The file specification <b>manweb</b> of the web browser <b>manweb</b>
       is to invoke
       to display documentation (except when it uses <b>man</b> to display
       a conventional man page).
       If the file specification does not include a slash, <b>manweb</b>
       searches for the file in the PATH search path.

       <p>If you don't specify this, the default is the value of the
       <b>BROWSER</b> environment variable, and if that is not set,
       <b>lynx</b>.
</dl>

Example:
<pre>
# Configuration file for Manweb

webdir=/usr/share/manweb
browser=netscape
</pre>


</body> </html>