Opera Search.ini editor is a great product (the link is in German, but download links are available at the bottom). The search.ini editor allows you to add and change the default search engines in Opera.
The search.ini editor allows you to both export your custom engines from Opera, and it also allows you to import the engines. I have created a few engines I use regularily. Install the search.ini editor, and run it once. After that, you should be able to install these engines by just clicking on the links.
* “Search Virtuelvis”:http://virtuelvis.com/download/opera/search/virtuelvis.se7 using the search keyword “bv”.
* “Search Merriam-Webster Online Dictionary”:http://virtuelvis.com/download/opera/search/mwd.se7 using “md”.
* “Search Merriam-Webster Online Thesaurus”:http://virtuelvis.com/download/opera/search/mwt.se7 using “mt”.
* “Go directly to numbered RFC”:http://virtuelvis.com/download/opera/search/rfc.se7 using “rfc”. Example: rfc 1149.
* “Go directly to W3C Technical recommendation”:http://virtuelvis.com/download/opera/search/w3tr.se7 using “tr”. Example: tr CSS2.
* “Validate HTML”:http://virtuelvis.com/download/opera/search/w3val.se7 using “val”. Example: val http://virtuelvis.com/.
* *Update:* “Search for PHP function”:http://virtuelvis.com/download/opera/search/phpfunction.se7 using “php”. Example:php array_search.
If you do not want to install the search.ini editor, there is also a guide to “modifying search.ini manually”:http://www.schrode.net/opera/search/search_ini.html