bash code to change write commands to not allow user to write code example

Example 1: linux chmod permissions

The three rightmost digits define permissions for the:
file user, the group, and others. 

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

Example 2: bash permissions

# 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      |
# -------------------------------------------------- +