File Permissions

The Linux kernel uses file permissions as the most basic access control mechanism.  The file permissions are represented by the first field you see in 'ls -l' output:

 $ ls -la
 drwxr-xr-x  2 reegen reegen   4096 Apr 19  2000 .
 drwxr-xr-x  2 root   root     4096 Feb 21  1973 ..
 -rw-------  1 reegen reegen   9663 Oct  8 16:03 .profile
 -rw-r--r--  1 reegen reegen   9663 Oct  8 16:03 .plan
 drwxrwxrwx  1 reegen reegen   4096 Jan 22 10:05 dropbox
 drwxr-x---  1 reegen friends  8925 Jan 12 11:17 music
 drwx------  1 reegen reegen   4096 Dec  6  8:50 private