shell permissions code example

Example 1: bash how do permissions work

# How permissions/changing permissions works in linux. Permissions are
#	generally listed in a format like rwxrw-r--, where r, w, x, and - 
#	stand for read, write, execute, and no permission respectively. There 
#	are basically three groups of rwx permissions: user, group, others
#	and depending on your relationship to the files, you might be any one
#	of these. 

#	To change file permissions, (e.g. chmod ### file), you need to 
#	indicate three decimal digits (0-7) which specify the three sets
#	of permissionswhen converted to binary. Briefly, a decimal number
#	between 0 and 7 can be represented by a three digit binary string.
#	The binary string sets the permissions by treating 1 as "true" or 
#	permission granted and 0 as "false", or permission denied. See the
#	table below for all the conversions and their meanings:

Decimal		Binary		Permission		Permission meaning
7			111			rwx				read, write, and execute
6			110			rw-				read and write
5			101			r-x				read and execute
4			100			r--				read only
3			011			-wx				write and execute
2			010			-w-				write only
1			001			--x				execute only
0			000			---				none

Example 2: linux permission

# syntax
# chmod *<Owner-digit>*<Group-digit>*<Others-digit> *<filename>

# example 
chmod 777 FileForEveryone.txt

# --------------------------------------------------------------

# +-------------+---------+---------+---------+
# | Command     | Owner   | Group   | Others  |
# +-------------+---------+---------+---------+
# | chmod 777   |   rwx   |   rwx   |   rwx   |
# | chmod 666   |   rw-   |   rw-   |   rw-   |
# | chmod 555   |   r-x   |   r-x   |   r-x   |
# | chmod 444   |   r--   |   r--   |   r--   |
# | chmod 333   |   -wx   |   -wx   |   -wx   |
# | chmod 222   |   -w-   |   -w-   |   -w-   |
# | chmod 111   |   --x   |   --x   |   --x   |
# | chmod 000   |   ---   |   ---   |   ---   |
# +-------------+---------+---------+---------+
# | chmod 776   |   rwx   |   rwx   |   rw-   |
# | chmod 766   |   rwx   |   rw-   |   rw-   |
# | chmod 765   |   rwx   |   rw-   |   r-x   |
# +-------------+---------+---------+---------+

# ENTITIES
# -------------------------------------------------- +
# Owner:	User that created the file               |
# Group:	Users in the same group as the owner     |
# Others:	The rest of the users on the system      |
# -------------------------------------------------- +