====== File_Permissions ======

**File Permissions and chmod**

Original = http://www.redbrick.dcu.ie/help


 Permission Binary Octal
 <br>
 rwx        111    7
 rw-        110    6 
 r-x        101    5
 r--        100    4
 -wx        011    3
 -w-        010    2
 --x        001    1
 ---        000    0

For permission rw-------, use 600.<br>
For permission rwx--x--x, use 711.<br>
For permission rw-r--r--, use 644.

chmod -R 600 files/directory

====== Sticky Bit ======
Case: Take a website folder. We want two users to be able to both read/write into this folder. We can add both users to a new group on the server, and by setting the sgid we can have it so that any files created in that folder will be of the parent group (as opposed to the default user group).
Take the following example:
 groupadd testgroup
 adduser existingusername1 testgroup
 adduser existingusername1 testgroup
 mkdir /srv/vhost/website
 chown existingusername1:testgroup /srv/vhost/website
 chmod 2775 /srv/vhost/website
 su existingusername1
 touch /srv/vhost/website/testfile
 chmod 755 /srv/vhost/website/testfile
 ls -la /srv/vhost/website
 
 drwxrwsr-x 2 existinguser1  testgroup   4096 2008-05-24 00:04 .
 drwxrwxr-x 6 root           root        4096 2008-05-23 23:48 ..
 -rwxrwxr-x 1 existinguser1  testgroup      0 2008-05-24 00:04 testfile

Any files created by either username will be created in the "testgroup" group.

Excellent SGID and SUID and Sticky explaination: http://www.zzee.com/solutions/linux-permissions.shtml#setuid