= Linux File & Directory Permissions

Every Linux file and directory has an owner. Each file or directory also belongs to a group. The permissions which can be assigned to a file are **read**, **write** and **eXecute**. These permissions are assigned separately for the file **owner**, members of the **group** to which the file belongs and finally for everyone else. 

File permissions are generally shown in one of two formats on Linux. The first is a string of letters. For example:

  drwxrwxrwx
  -rwxrw-r--

* This is decoded as d = directory.
* The next 3 characters are the owner permissions: r = read; w = write and x = exectute.
* The second set of 3 characters (skipping the directory indicator) are the group permissions
* The last 3 characters are the permissions for everyone else. A "-" indicates no permission.

The second way of indicating the same information is a shorthand 3 digit number. The following table explains how the values are determined.

^  ^  Owner  ^  Group  ^  Other  ^
^permission  |  r w x  |  r w x  |  r w x  |
^value  |  4 2 1  |  4 2 1  |  4 2 1  |

Sum for each set and concatenate. Thus all permissions for everyone would be 7 & 7 & 7 or 777

Change permissions from console using sudo((sudo is a command used on some Linux systems to give temporary administrator permission to a user. If you are using SSH on a remote server you would omit the sudo and just give the rest of the command.))
  sudo chmod [-R] 777 [dir or file name(s)]

-R implies recursively setting for all sub directories at or under given.

Change owner and group with chown
  sudo chown [-R] owner:group files

To change just files, not directories
	sudo find . -type f -exec [chmod or chown] [settings] {} \;
for only directories use "-type f" instead of "-type d"

Example: change all directories permissions to 755:
	sudo find . -type d -exec chmod 755 {} \;



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