What's a file?
`ls -l`

     % ls -l
     total 538400
     drwxr-xr-x  3 mjd users    4096 2007-11-22 21:01 bin
     drwxr-xr-x  2 mjd users   12288 2007-10-12 18:42 Camera
     -rw-r--r--  1 mjd users     901 2007-09-09 14:39 deltahedra
     -rw-r--r--  1 mjd users     676 2007-09-09 14:35 deltahedra~
     drwxr-xr-x 18 mjd users   16384 2007-12-01 11:54 Desktop
     -rw-r--r--  1 mjd users     118 2007-09-18 23:01 DNS
     drwxr-xr-x  2 mjd users    4096 2007-10-20 14:13 Documents
     dr-xr-x---  7 mjd users    4096 2007-02-19 01:18 dreamhost
     drwxr-xr-x  2 mjd users    4096 2007-11-29 03:03 dwhelper
     lrwxrwxrwx  1 mjd users      26 2007-06-12 08:28 Examples -> /usr/share/example-content
     ...
What's all that stuff?