Yub.js is an extensible client-side web command-line that comes with loads of useful search engines and shortcuts, reusable commands, and lots of other hidden goodies like stopwatches and inline YouTube videos. It also has a flexible API so you can call yub.js commands from anywhere: for example, you can link directly to commands, or access them right from your browser address bar (just set up a single search shortcut pointing at the yub.js API, and get hundreds of other search shortcuts for free). The list of available search engines is completely modular: you can drop in your own list of commonly visited websites by editing or replacing the mods.js file (json). Making your own new commands is easy -- just use the create command (with the name of the new command as an optional argument). Feel free to add your own new functions or extend existing ones by editing functions.js. Oh, and regular expressions are supported everywhere by default.