The question is that I want to toggle of the executable bit of a linux executable I know that I can set a+x executable, but I can't set is as NOT executable :( Google omits not from searches..
CHMOD is used to change permissions of a file. PERMISSION COMMAND
Here is another way of looking at it:
To get a combination, just add them up. For example, to get read, write, execute by owner, read, execute, by group, and execute by anybody, you would add 400+200+100+040+010+001 to give 751.
Easiest way without changing other settings:
From man chmod:
mode ::= clause [, clause ...] clause ::= [who ...] [action ...] action action ::= op [perm ...] who ::= a | u | g | o op ::= + | - | = perm ::= r | s | t | w | x | X | u | g | o
Notice the three options in op: