I'm new to web development (and to this forum), and I'm having some trouble.

I was asked to help out with a friend's corporate website. When I took a look at things with my FTP program, I found a bunch of folders with unfamiliar names. Because I've always done development on less-sophisticated systems, I have no idea what I'm looking at and how it will affect any PHP code I write.

The folders are:
  • tmp
  • html
  • logs
  • stats
  • _sitedata
  • www
  • var
  • usr
  • sbin
  • root
  • private
  • lib
  • etc
  • dev
  • bin

If y'all could just point me in the right direction or to some helpful literature, I'd love to learn more about what I'm looking at.