How do you enable permits r/w for the system resources?

Santiago

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I want to edit parts of the system file such as ,Tiff files and some text. Every time I try I get a message that says I have no privileges to move or erase / replace this files.

I have tried "chmod" from the terminal but I still have no succes getting a message alert that command could not be used because of privileges or something.

In the system I am the Administrator and I still cant change the system file. This is a protection system but what if you just want to mess up some things like the Login screen.

Any tips will be great thanks.
 

schnell

Registered
This information has been submitted elsewhere as a 'hack' (to MacFixit.com), but it isn't really. To be honest, I'm not completely sure myself exactly how it's implemented, but I will describe what's necessary.

At the heart of the Unix concept of multiple users (and hence what their permissions are) is the file /etc/passwd. This contains a list of system users, their shells, and their user IDs. The user ID of 0 (zero) represents the system administrator, who has access to all files and directories. Unlike OSes like Lucent's Plan 9 or "trusted" operating systems used in security-intensive military and other situations, the Unix concept of administration has one user who has access to everything, and other users who have limited access to other resources.

Usually, this Unix user ID 0 is referred to as "root" (Windows NT/2000 implements the same concept under the username "Administrator"). If you look at the system files that you're attempting to administer from a Unix console point of view (/MacOS X/Applications/Utilities/Terminal.app), these files are all owned by "root," with only "root" set up to have the priviliges to modify these files.

When you install MacOS X Public Beta, you are prompted to create a username and password; the "user" you create "will have administrative priviliges," you are told. This is true, to an extent - but not fully. You are allowed by the MacOS X GUI to do things that only the Unix "root" can do - but there is no entry in /etc/passwd for your username (although, mysteriously, files can be owned by you).

Although as a BSD sysadmin this shames me to admit, this takes place somewhere in MacOS X that I haven't had time to find out. If I get the chance to search some more and find out how this works, I will post it here (or if someone else already knows, please post ;) ).

Functionally, what happens is that your MacOS X login is translated to having "root" privileges (probably in some MacOS X-specific setup which places you in the same group as root or functionally gives you a User ID of 0. However, you still aren't identified when you log into the terminal environment as "root," which is the user that owns these files.

To change them, use the Terminal app (listed above) and use the "su" command. This will prompt you for a password, which will be the same as that of the "administrative" user you set up originally. From there, you can modify/delete/etc. all the files you want, using Unix shell commands.

 

Santiago

Registered


But this kinda sucks.

In other words as a protective measure from Mac dudes to interfere with the system, those files are locked out.

I will try to use "su" and change stuff arround, though it is not very intuitive compared to: The file already exists do you want to replace it with the one you are moving (OK) (CANCEL)
 

mordaga

Registered
Is there anyway to determine the password for the "root" user?

Would you (I) then be able to log in as "root" to modify system stuff.

I would like to install my fonts directly into the system. If you install fonts at a higher level, they don't show up in Classic.
 

Santiago

Registered


I was able to log in as root with my admin password.

type:

su

then enter

then your old password. Then you will be logged in as root and will be able to do whatever you want with your system file. I changed my Login Screen to a cooler one just to test.

BE CAREFUL!!!

If you remove a file that is critical there is no going back, no second chances. And it is a fragile system file.
 

Luis Correia

Registered
I agree with Apple in not logging the regular "administrative" user as root. Great concept! Typical Mac users are used to poke their noses everywhere in the System Folder and changing things. If you have a copy of System Folder, things can be quickly restored without damage. But anything Unix based is not so forgiving regarding curious but often ignorant users. Past Mac experience and MacOS X GUI friendliness can give them a false sense of familiarity and safety, but they're headed for disaster if they aren't sure of what they're doing.
Let those who know "su" for true root privileges.
 

ebalch

Registered
Many of you probably already knew this but...

BTW, you can still login as "root" from the login panel too!

Just use root as the username and the "owner" user's password and you'll log in as the root with all the little locks set to unlocked and full root rights. Also, when you run terminal you'll see that you are "root".

Oh what fun!
 
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