======File Permissions=====

There are 6 permissions in Linux

These are the standard ones
**Read write execute**

^ File Type  ^  Owning User  ^  Owning group  ^  Other  ^
| d (directory)  |  rwx  |  r-x  |  ---  |

There are 3 special permissions

^  Permission ^ effect on directory ^ effect on file ^
| u+s (suid) | no effect | File executes as the user that owns the file, not as the user that ran the file|
| g+s (sgid) | Files that are created in the directory have a group owner to match the group owner of the directory| File executes as the group that owns the file. |
| o+t (sticky) | Users with write access to the directory can remove only files that they own; they cannot remove or force saves to files that other users own | no effect|

===Sticky bit===
  * This applies only to directories
  * Only the owning user can delete a file from a directory
  * Applied with **chmod o+t** or **chmod 1NNN**
  * Identified by a t in permissions for others

Permission will appear as a **T** if the execute permissions is not set for other. If this permission is set it will appear as lower case

===SetGid bit===
  * Set on files and directories
  * The owning group of a newly created file is derived from the directory that the file is created (for directory)
  * THe executables run with the permissions of the owning group of the executablers (for files)
  * To set use **chmod g+s /dir** or **chmod 2NNN /dir** or for files **chmod g+s /file** or **chmod 2NNN /file**
  * Identifed by an **s** in permissions for the owning group

===SetUID bit===
  * this is for files only
  * executables run with permissions of the owning user of the executable
  * to set use **chmod u+s /file** or **chmod 4NNN /file**
  * identified by an **s** in the owning user