is there anyway automatically reverse chmod/chown changes made?
there is few time i made chown and chmod that damages the files which process cant access it causing me to reformat my redhat9.

is there any guide that teaches files and folders that can be change its ownership and access permision and files and folders that should have spesifec ownership and permission

i had accidentally chmod -Rv a+rwx /usr

No way that I know of other than manually if you've already committed the actions you want to change. But there's a fantastic script for being able to restore them if you run it *before* making the changes.

http://www.linuxquestions.org/questi...threadid=91333

So, yeah - pretty much a manual task of hoping you get it right this time, I'm afraid. But better luck next time.

Basically, though, no one but root should have write access to /usr. Directories, executables, some libraries - I dunno - that stuff should be executable. Most everything else in /usr can be world readable (I think).