I use Solaris allot at work. Being a UNIX operating system its search functions, both in the OS and in VI are quite powerful. They are so good in fact that they can be a bit tricky to use. This is especially so when it comes to regular expressions.
Site net.tutsplus.com has a good post showing not only the 8 Regular Expressions You Should Know but it is also a good explaination of how they work.