Most shells have some provision for aliases. Aliases can assign default behavior to a command (for example "rm" is often aliased to "rm -i") or can be used to create new commands (a typical example is "ll" aliased to be "ls -l").
Your domain registration is critically important. It's easy to get lazy about this stuff. Often your ISP or whoever set up your web site said they'd "take care of it" and that was it. It's been working fine for years, and you don't have to worry about it.
When you are writing your own code, you are more apt to use someone else's module than write your own, unless your project gets fairly large and complex. Small scripting tasks just don't need the advantages modules offer.
A bit vector is just an array of bits; subsets of bits within the bytes have some meaning. That allows more compact storage for certain types of data. For example, if you only needed boolean on-off values, you can store eight values in one byte.
Google is now letting web sites submit an xml file that lists urls and some information about how often the pages change, and how important the page is relative to other pages. Basically, it gets you to do part of the work for them - which we would hope helps everyone.
When you are writing your own code, you are more apt to use someone else's module than write your own, unless your project gets fairly large and complex. Small scripting tasks just don't need the advantages modules offer. However, there is a case where modules might make perfect sense: web server cgi scripts often repeat the same tasks.
You can change the output of the console keyboard with loadkeys. It's an extremely powerful command, and the man page can be confusing, but for simple use (which is often all we need it for), it's very easy.