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<manualpage metafile="rewrite_guide.xml.meta">
  <parentdocument href="./">Rewrite</parentdocument>

  <title>URL Rewriting Guide</title>

  <summary>

    <p>This document supplements the <module>mod_rewrite</module>
    <a href="../mod/mod_rewrite.html">reference documentation</a>.
    It describes how one can use Apache's <module>mod_rewrite</module>
    to solve typical URL-based problems with which webmasters are
    commonly confronted. We give detailed descriptions on how to
    solve each problem by configuring URL rewriting rulesets.</p>

    <note type="warning">ATTENTION: Depending on your server configuration
    it may be necessary to slightly change the examples for your
    situation, e.g. adding the <code>[PT]</code> flag when
    additionally using <module>mod_alias</module> and
    <module>mod_userdir</module>, etc. Or rewriting a ruleset
    to fit in <code>.htaccess</code> context instead
    of per-server context. Always try to understand what a
    particular ruleset really does before you use it. This
    avoids many problems.</note>

  </summary>
<seealso><a href="../mod/mod_rewrite.html">Module
documentation</a></seealso>
<seealso><a href="intro.html">mod_rewrite
introduction</a></seealso>
<seealso><a href="rewrite_guide_advanced.html">Advanced Rewrite Guide - advanced 
useful examples</a></seealso>
<seealso><a href="tech.html">Technical details</a></seealso>


    <section id="moveddocroot">

      <title>Moved <code>DocumentRoot</code></title>

      <dl>
        <dt>Description:</dt>

        <dd>
<p>Usually the <directive module="core">DocumentRoot</directive>
of the webserver directly relates to the URL "<code>/</code>".
But often this data is not really of top-level priority. For example,
you may wish for visitors, on first entering a site, to go to a
particular subdirectory <code>/about/</code>. This may be accomplished
using the following ruleset:</p>
</dd>

        <dt>Solution:</dt>

        <dd>
          <p>We redirect the URL <code>/</code> to
          <code>/about/</code>:
          </p>
         
<example><pre>
RewriteEngine on
RewriteRule   <strong>^/$</strong>  /about/  [<strong>R</strong>]
</pre></example>

    <p>Note that this can also be handled using the <directive
    module="mod_alias">RedirectMatch</directive> directive:</p>

<example>
RedirectMatch ^/$ http://example.com/about/
</example>

<p>Note also that the example rewrites only the root URL. That is, it
rewrites a request for <code>http://example.com/</code>, but not a
request for <code>http://example.com/page.html</code>. If you have in 
fact changed your document root - that is, if <strong>all</strong> of 
your content is in fact in that subdirectory, it is greatly preferable 
to simply change your <directive module="core">DocumentRoot</directive>
directive, rather than rewriting URLs.</p>
</dd>
</dl>

    </section>

    <section id="trailingslash">

      <title>Trailing Slash Problem</title>

      <dl>
        <dt>Description:</dt>

    <dd><p>The vast majority of "trailing slash" problems can be dealt
    with using the techniques discussed in the <a
    href="http://httpd.apache.org/docs/misc/FAQ-E.html#set-servername">FAQ
    entry</a>. However, occasionally, there is a need to use mod_rewrite
    to handle a case where a missing trailing slash causes a URL to
    fail. This can happen, for example, after a series of complex
    rewrite rules.</p>
    </dd>

        <dt>Solution:</dt>

        <dd>
          <p>The solution to this subtle problem is to let the server
          add the trailing slash automatically. To do this
          correctly we have to use an external redirect, so the
          browser correctly requests subsequent images etc. If we
          only did a internal rewrite, this would only work for the
          directory page, but would go wrong when any images are
          included into this page with relative URLs, because the
          browser would request an in-lined object. For instance, a
          request for <code>image.gif</code> in
          <code>/~quux/foo/index.html</code> would become
          <code>/~quux/image.gif</code> without the external
          redirect!</p>

          <p>So, to do this trick we write:</p>

<example><pre>
RewriteEngine  on
RewriteBase    /~quux/
RewriteRule    ^foo<strong>$</strong>  foo<strong>/</strong>  [<strong>R</strong>]
</pre></example>

   <p>Alternately, you can put the following in a
   top-level <code>.htaccess</code> file in the content directory.
   But note that this creates some processing overhead.</p>

<example><pre>
RewriteEngine  on
RewriteBase    /~quux/
RewriteCond    %{REQUEST_FILENAME}  <strong>-d</strong>
RewriteRule    ^(.+<strong>[^/]</strong>)$           $1<strong>/</strong>  [R]
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="setenvvars">

      <title>Set Environment Variables According To URL Parts</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>Perhaps you want to keep status information between
          requests and use the URL to encode it. But you don't want
          to use a CGI wrapper for all pages just to strip out this
          information.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>We use a rewrite rule to strip out the status information
          and remember it via an environment variable which can be
          later dereferenced from within XSSI or CGI. This way a
          URL <code>/foo/S=java/bar/</code> gets translated to
          <code>/foo/bar/</code> and the environment variable named
          <code>STATUS</code> is set to the value "java".</p>

<example><pre>
RewriteEngine on
RewriteRule   ^(.*)/<strong>S=([^/]+)</strong>/(.*)    $1/$3 [E=<strong>STATUS:$2</strong>]
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="redirecthome">

      <title>Redirect Homedirs For Foreigners</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>We want to redirect homedir URLs to another webserver
          <code>www.somewhere.com</code> when the requesting user
          does not stay in the local domain
          <code>ourdomain.com</code>. This is sometimes used in
          virtual host contexts.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>Just a rewrite condition:</p>

<example><pre>
RewriteEngine on
RewriteCond   %{REMOTE_HOST}  <strong>!^.+\.ourdomain\.com$</strong>
RewriteRule   ^(/~.+)         http://www.somewhere.com/$1 [R,L]
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="redirectanchors">

      <title>Redirecting Anchors</title>

      <dl>
        <dt>Description:</dt>

        <dd>
        <p>By default, redirecting to an HTML anchor doesn't work,
        because mod_rewrite escapes the <code>#</code> character,
        turning it into <code>%23</code>. This, in turn, breaks the
        redirection.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>Use the <code>[NE]</code> flag on the
          <code>RewriteRule</code>. NE stands for No Escape.
          </p>
        </dd>
      </dl>

    </section>

    <section id="time-dependent">

      <title>Time-Dependent Rewriting</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>When tricks like time-dependent content should happen a
          lot of webmasters still use CGI scripts which do for
          instance redirects to specialized pages. How can it be done
          via <module>mod_rewrite</module>?</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>There are a lot of variables named <code>TIME_xxx</code>
          for rewrite conditions. In conjunction with the special
          lexicographic comparison patterns <code>&lt;STRING</code>,
          <code>&gt;STRING</code> and <code>=STRING</code> we can
          do time-dependent redirects:</p>

<example><pre>
RewriteEngine on
RewriteCond   %{TIME_HOUR}%{TIME_MIN} &gt;0700
RewriteCond   %{TIME_HOUR}%{TIME_MIN} &lt;1900
RewriteRule   ^foo\.html$             foo.day.html
RewriteRule   ^foo\.html$             foo.night.html
</pre></example>

          <p>This provides the content of <code>foo.day.html</code>
          under the URL <code>foo.html</code> from
          <code>07:01-18:59</code> and at the remaining time the
          contents of <code>foo.night.html</code>. Just a nice
          feature for a homepage...</p>

          <note type="warning"><module>mod_cache</module>, intermediate proxies
          and browsers may each cache responses and cause the either page to be
          shown outside of the time-window configured.
          <module>mod_expires</module> may be used to control this
          effect.</note>

        </dd>
      </dl>

    </section>

    <section id="structuredhomedirs">

      <title>Structured Homedirs</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>Some sites with thousands of users use a
          structured homedir layout, <em>i.e.</em> each homedir is in a
          subdirectory which begins (for instance) with the first
          character of the username. So, <code>/~foo/anypath</code>
          is <code>/home/<strong>f</strong>/foo/.www/anypath</code>
          while <code>/~bar/anypath</code> is
          <code>/home/<strong>b</strong>/bar/.www/anypath</code>.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>We use the following ruleset to expand the tilde URLs
          into the above layout.</p>

<example><pre>
RewriteEngine on
RewriteRule   ^/~(<strong>([a-z])</strong>[a-z0-9]+)(.*)  /home/<strong>$2</strong>/$1/.www$3
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="dynamic-mirror">

      <title>Dynamic Mirror</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>Assume there are nice web pages on remote hosts we want
          to bring into our namespace. For FTP servers we would use
          the <code>mirror</code> program which actually maintains an
          explicit up-to-date copy of the remote data on the local
          machine. For a web server we could use the program
          <code>webcopy</code> which runs via HTTP. But both
          techniques have a major drawback: The local copy is
          always only as up-to-date as the last time we ran the program. It
          would be much better if the mirror was not a static one we
          have to establish explicitly. Instead we want a dynamic
          mirror with data which gets updated automatically
          as needed on the remote host(s).</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>To provide this feature we map the remote web page or even
          the complete remote web area to our namespace by the use
          of the <dfn>Proxy Throughput</dfn> feature
          (flag <code>[P]</code>):</p>

<example><pre>
RewriteEngine  on
RewriteBase    /~quux/
RewriteRule    ^<strong>hotsheet/</strong>(.*)$  <strong>http://www.tstimpreso.com/hotsheet/</strong>$1  [<strong>P</strong>]
</pre></example>

<example><pre>
RewriteEngine  on
RewriteBase    /~quux/
RewriteRule    ^<strong>usa-news\.html</strong>$   <strong>http://www.quux-corp.com/news/index.html</strong>  [<strong>P</strong>]
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="retrieve-missing-data">

      <title>Retrieve Missing Data from Intranet</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>This is a tricky way of virtually running a corporate
          (external) Internet web server
          (<code>www.quux-corp.dom</code>), while actually keeping
          and maintaining its data on an (internal) Intranet web server
          (<code>www2.quux-corp.dom</code>) which is protected by a
          firewall. The trick is that the external web server retrieves
          the requested data on-the-fly from the internal
          one.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>First, we must make sure that our firewall still
          protects the internal web server and only the
          external web server is allowed to retrieve data from it.
          On a packet-filtering firewall, for instance, we could
          configure a firewall ruleset like the following:</p>

<example><pre>
<strong>ALLOW</strong> Host www.quux-corp.dom Port &gt;1024 --&gt; Host www2.quux-corp.dom Port <strong>80</strong>
<strong>DENY</strong>  Host *                 Port *     --&gt; Host www2.quux-corp.dom Port <strong>80</strong>
</pre></example>

          <p>Just adjust it to your actual configuration syntax.
          Now we can establish the <module>mod_rewrite</module>
          rules which request the missing data in the background
          through the proxy throughput feature:</p>

<example><pre>
RewriteRule ^/~([^/]+)/?(.*)          /home/$1/.www/$2 [C]
# REQUEST_FILENAME usage below is correct in this per-server context example 
# because the rule that references REQUEST_FILENAME is chained to a rule that
# sets REQUEST_FILENAME. 
RewriteCond %{REQUEST_FILENAME}       <strong>!-f</strong>
RewriteCond %{REQUEST_FILENAME}       <strong>!-d</strong>
RewriteRule ^/home/([^/]+)/.www/?(.*) http://<strong>www2</strong>.quux-corp.dom/~$1/pub/$2 [<strong>P</strong>]
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="new-mime-type">

      <title>New MIME-type, New Service</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>On the net there are many nifty CGI programs. But
          their usage is usually boring, so a lot of webmasters
          don't use them. Even Apache's Action handler feature for
          MIME-types is only appropriate when the CGI programs
          don't need special URLs (actually <code>PATH_INFO</code>
          and <code>QUERY_STRINGS</code>) as their input. First,
          let us configure a new file type with extension
          <code>.scgi</code> (for secure CGI) which will be processed
          by the popular <code>cgiwrap</code> program. The problem
          here is that for instance if we use a Homogeneous URL Layout
          (see above) a file inside the user homedirs might have a URL
          like <code>/u/user/foo/bar.scgi</code>, but
          <code>cgiwrap</code> needs URLs in the form
          <code>/~user/foo/bar.scgi/</code>. The following rule
          solves the problem:</p>

<example><pre>
RewriteRule ^/[uge]/<strong>([^/]+)</strong>/\.www/(.+)\.scgi(.*) ...
... /internal/cgi/user/cgiwrap/~<strong>$1</strong>/$2.scgi$3  [NS,<strong>T=application/x-http-cgi</strong>]
</pre></example>

          <p>Or assume we have some more nifty programs:
          <code>wwwlog</code> (which displays the
          <code>access.log</code> for a URL subtree) and
          <code>wwwidx</code> (which runs Glimpse on a URL
          subtree). We have to provide the URL area to these
          programs so they know which area they are really working with.
          But usually this is complicated, because they may still be
          requested by the alternate URL form, i.e., typically we would
          run the <code>swwidx</code> program from within
          <code>/u/user/foo/</code> via hyperlink to</p>

<example><pre>
/internal/cgi/user/swwidx?i=/u/user/foo/
</pre></example>

          <p>which is ugly, because we have to hard-code
          <strong>both</strong> the location of the area
          <strong>and</strong> the location of the CGI inside the
          hyperlink. When we have to reorganize, we spend a
          lot of time changing the various hyperlinks.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>The solution here is to provide a special new URL format
          which automatically leads to the proper CGI invocation.
          We configure the following:</p>

<example><pre>
RewriteRule   ^/([uge])/([^/]+)(/?.*)/\*  /internal/cgi/user/wwwidx?i=/$1/$2$3/
RewriteRule   ^/([uge])/([^/]+)(/?.*):log /internal/cgi/user/wwwlog?f=/$1/$2$3
</pre></example>

          <p>Now the hyperlink to search at
          <code>/u/user/foo/</code> reads only</p>

<example><pre>
HREF="*"
</pre></example>

          <p>which internally gets automatically transformed to</p>

<example><pre>
/internal/cgi/user/wwwidx?i=/u/user/foo/
</pre></example>

          <p>The same approach leads to an invocation for the
          access log CGI program when the hyperlink
          <code>:log</code> gets used.</p>
        </dd>
      </dl>

    </section>

    <section id="autorefresh">

      <title>Document With Autorefresh</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>Wouldn't it be nice, while creating a complex web page, if
          the web browser would automatically refresh the page every
          time we save a new version from within our editor?
          Impossible?</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>No! We just combine the MIME multipart feature, the
          web server NPH feature, and the URL manipulation power of
          <module>mod_rewrite</module>. First, we establish a new
          URL feature: Adding just <code>:refresh</code> to any
          URL causes the 'page' to be refreshed every time it is
          updated on the filesystem.</p>

<example><pre>
RewriteRule   ^(/[uge]/[^/]+/?.*):refresh  /internal/cgi/apache/nph-refresh?f=$1
</pre></example>

          <p>Now when we reference the URL</p>

<example><pre>
/u/foo/bar/page.html:refresh
</pre></example>

          <p>this leads to the internal invocation of the URL</p>

<example><pre>
/internal/cgi/apache/nph-refresh?f=/u/foo/bar/page.html
</pre></example>

          <p>The only missing part is the NPH-CGI script. Although
          one would usually say "left as an exercise to the reader"
          ;-) I will provide this, too.</p>

<example><pre>
#!/sw/bin/perl
##
##  nph-refresh -- NPH/CGI script for auto refreshing pages
##  Copyright (c) 1997 Ralf S. Engelschall, All Rights Reserved.
##
$| = 1;

#   split the QUERY_STRING variable
@pairs = split(/&amp;/, $ENV{'QUERY_STRING'});
foreach $pair (@pairs) {
    ($name, $value) = split(/=/, $pair);
    $name =~ tr/A-Z/a-z/;
    $name = 'QS_' . $name;
    $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
    eval "\$$name = \"$value\"";
}
$QS_s = 1 if ($QS_s eq '');
$QS_n = 3600 if ($QS_n eq '');
if ($QS_f eq '') {
    print "HTTP/1.0 200 OK\n";
    print "Content-type: text/html\n\n";
    print "&amp;lt;b&amp;gt;ERROR&amp;lt;/b&amp;gt;: No file given\n";
    exit(0);
}
if (! -f $QS_f) {
    print "HTTP/1.0 200 OK\n";
    print "Content-type: text/html\n\n";
    print "&amp;lt;b&amp;gt;ERROR&amp;lt;/b&amp;gt;: File $QS_f not found\n";
    exit(0);
}

sub print_http_headers_multipart_begin {
    print "HTTP/1.0 200 OK\n";
    $bound = "ThisRandomString12345";
    print "Content-type: multipart/x-mixed-replace;boundary=$bound\n";
    &amp;print_http_headers_multipart_next;
}

sub print_http_headers_multipart_next {
    print "\n--$bound\n";
}

sub print_http_headers_multipart_end {
    print "\n--$bound--\n";
}

sub displayhtml {
    local($buffer) = @_;
    $len = length($buffer);
    print "Content-type: text/html\n";
    print "Content-length: $len\n\n";
    print $buffer;
}

sub readfile {
    local($file) = @_;
    local(*FP, $size, $buffer, $bytes);
    ($x, $x, $x, $x, $x, $x, $x, $size) = stat($file);
    $size = sprintf("%d", $size);
    open(FP, "&amp;lt;$file");
    $bytes = sysread(FP, $buffer, $size);
    close(FP);
    return $buffer;
}

$buffer = &amp;readfile($QS_f);
&amp;print_http_headers_multipart_begin;
&amp;displayhtml($buffer);

sub mystat {
    local($file) = $_[0];
    local($time);

    ($x, $x, $x, $x, $x, $x, $x, $x, $x, $mtime) = stat($file);
    return $mtime;
}

$mtimeL = &amp;mystat($QS_f);
$mtime = $mtime;
for ($n = 0; $n &amp;lt; $QS_n; $n++) {
    while (1) {
        $mtime = &amp;mystat($QS_f);
        if ($mtime ne $mtimeL) {
            $mtimeL = $mtime;
            sleep(2);
            $buffer = &amp;readfile($QS_f);
            &amp;print_http_headers_multipart_next;
            &amp;displayhtml($buffer);
            sleep(5);
            $mtimeL = &amp;mystat($QS_f);
            last;
        }
        sleep($QS_s);
    }
}

&amp;print_http_headers_multipart_end;

exit(0);

##EOF##
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="mass-virtual-hosting">

      <title>Mass Virtual Hosting</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>The <directive type="section" module="core"
          >VirtualHost</directive> feature of Apache is nice
          and works great when you just have a few dozen
          virtual hosts. But when you are an ISP and have hundreds of
          virtual hosts, this feature is suboptimal.</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>To provide this feature we map the remote web page or even
          the complete remote web area to our namespace using the
          <dfn>Proxy Throughput</dfn> feature (flag <code>[P]</code>):</p>

<example><pre>
##
##  vhost.map
##
www.vhost1.dom:80  /path/to/docroot/vhost1
www.vhost2.dom:80  /path/to/docroot/vhost2
     :
www.vhostN.dom:80  /path/to/docroot/vhostN
</pre></example>

<example><pre>
##
##  httpd.conf
##
    :
#   use the canonical hostname on redirects, etc.
UseCanonicalName on

    :
#   add the virtual host in front of the CLF-format
CustomLog  /path/to/access_log  "%{VHOST}e %h %l %u %t \"%r\" %&gt;s %b"
    :

#   enable the rewriting engine in the main server
RewriteEngine on

#   define two maps: one for fixing the URL and one which defines
#   the available virtual hosts with their corresponding
#   DocumentRoot.
RewriteMap    lowercase    int:tolower
RewriteMap    vhost        txt:/path/to/vhost.map

#   Now do the actual virtual host mapping
#   via a huge and complicated single rule:
#
#   1. make sure we don't map for common locations
RewriteCond   %{REQUEST_URI}  !^/commonurl1/.*
RewriteCond   %{REQUEST_URI}  !^/commonurl2/.*
    :
RewriteCond   %{REQUEST_URI}  !^/commonurlN/.*
#
#   2. make sure we have a Host header, because
#      currently our approach only supports
#      virtual hosting through this header
RewriteCond   %{HTTP_HOST}  !^$
#
#   3. lowercase the hostname
RewriteCond   ${lowercase:%{HTTP_HOST}|NONE}  ^(.+)$
#
#   4. lookup this hostname in vhost.map and
#      remember it only when it is a path
#      (and not "NONE" from above)
RewriteCond   ${vhost:%1}  ^(/.*)$
#
#   5. finally we can map the URL to its docroot location
#      and remember the virtual host for logging purposes
RewriteRule   ^/(.*)$   %1/$1  [E=VHOST:${lowercase:%{HTTP_HOST}}]
    :
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="proxy-deny">

      <title>Proxy Deny</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>How can we forbid a certain host or even a user of a
          special host from using the Apache proxy?</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>We first have to make sure <module>mod_rewrite</module>
          is below(!) <module>mod_proxy</module> in the Configuration
          file when compiling the Apache web server. This way it gets
          called <em>before</em> <module>mod_proxy</module>. Then we
          configure the following for a host-dependent deny...</p>

<example><pre>
RewriteCond %{REMOTE_HOST} <strong>^badhost\.mydomain\.com$</strong>
RewriteRule !^http://[^/.]\.mydomain.com.*  - [F]
</pre></example>

          <p>...and this one for a user@host-dependent deny:</p>

<example><pre>
RewriteCond %{REMOTE_IDENT}@%{REMOTE_HOST}  <strong>^badguy@badhost\.mydomain\.com$</strong>
RewriteRule !^http://[^/.]\.mydomain.com.*  - [F]
</pre></example>
        </dd>
      </dl>

    </section>

    <section id="referer-deflector">

      <title>Referer-based Deflector</title>

      <dl>
        <dt>Description:</dt>

        <dd>
          <p>How can we program a flexible URL Deflector which acts
          on the "Referer" HTTP header and can be configured with as
          many referring pages as we like?</p>
        </dd>

        <dt>Solution:</dt>

        <dd>
          <p>Use the following really tricky ruleset...</p>

<example><pre>
RewriteMap  deflector txt:/path/to/deflector.map

RewriteCond %{HTTP_REFERER} !=""
RewriteCond ${deflector:%{HTTP_REFERER}} ^-$
RewriteRule ^.* %{HTTP_REFERER} [R,L]

RewriteCond %{HTTP_REFERER} !=""
RewriteCond ${deflector:%{HTTP_REFERER}|NOT-FOUND} !=NOT-FOUND
RewriteRule ^.* ${deflector:%{HTTP_REFERER}} [R,L]
</pre></example>

          <p>... in conjunction with a corresponding rewrite
          map:</p>

<example><pre>
##
##  deflector.map
##

http://www.badguys.com/bad/index.html    -
http://www.badguys.com/bad/index2.html   -
http://www.badguys.com/bad/index3.html   http://somewhere.com/
</pre></example>

          <p>This automatically redirects the request back to the
          referring page (when "<code>-</code>" is used as the value
          in the map) or to a specific URL (when an URL is specified
          in the map as the second argument).</p>
        </dd>
      </dl>

    </section>


</manualpage>