Below is a script which makes a search plugin for arbitrary site.

It can create plugin not only for search engines but for any dynamic site which accepts CGI parameters.

To create search plugin:

1. Make a search of bareword searchTerms, then copy a url appeared in address bar of a browser
2. Run the script with that url as parameter
3. Redirect script output to .xml file in searchplugins directory of your firefox profile

As an example let's create search plugin for LiveJournal

1. Search 'searchTerms' using the search form
Got url http://search.livejournal.ru/ljsearch?query=searchTerms&ie=utf-8
2. run the script with url as parameter

   perl mksp.pl Livejournal 'http://search.livejournal.ru/ljsearch?query=
   +searchTerms&ie=utf-8' > ~/.mozilla/firefox/ze02d000.default/searchplu
   +gins/lj.xml
   [download]

3. restart FireFox and enjoy with blue pen of LiveJournal in search plugins

#!/usr/bin/perl --

use strict;
use LWP::Simple;
use MIME::Base64 qw(encode_base64);

die "Usage: $0 Name 'SearchURLString'\n" if @ARGV < 2;

my ($name, $url) = @ARGV;

my ($site) = split '(?<![:/])/', $url;

my $ico = get($site . '/favicon.ico');
unless ($ico) {
    $site =~ s{http://[^.]+\.}{http://};
    $ico = get($site . '/favicon.ico');
}

die "Can't get favicon for $site\n" unless defined $ico;

my $base64 = encode_base64($ico);

$url =~ s/searchTerms/{searchTerms}/gi;
$url =~ s/&(?!amp;)/&amp;/g;

print <<END_OF_SEARCHPLUGIN;
<SearchPlugin
  xmlns="http://www.mozilla.org/2006/browser/search/"
  xmlns:os="http://a9.com/-/spec/opensearch/1.1/">
<os:ShortName>$name</os:ShortName>
<os:Description>$name</os:Description>
<os:InputEncoding>UTF-8</os:InputEncoding>
<os:Image width="16" height="16">
  data:image/x-icon;base64,$base64</os:Image>
<SearchForm>$site</SearchForm>
<os:Url type="text/html" method="GET" template="$url">
</os:Url>
</SearchPlugin>
END_OF_SEARCHPLUGIN
__END__
[download]