What are the groups of Mac OS

Question

Hi
Who can explain to me what are the groups "staff", "system", "admin",  I saw "wheel" also, and others
What is their meaning and what is their action ?
Thanks

Answer 1

clbobman wrote:
Also to reiterate. I am not part of a NETWORK. I live at home with my wife. Why can I not just be ONE USER! Is it possible?
Hello, clbobman!
Please note that is topic has been dormant for two years. Since few people are likely to still be following it, it would be better to start a new topic of your own if you need help with this, preferably in the forum for the OS version you are using.
With that out of the way, please be aware that you are most certainly part a network. It is the Internet, the largest one on the planet! As was mentioned by several contributors back when this topic was active, users & groups exist largely to protect your privacy & security from the millions & millions of other users who share that vast network with you.
Unfortunately, an ever increasing number of those users are criminals who would like nothing better than for you to run an OS that provided little or nothing to prevent them from taking over control of your computer remotely, stealing the personal & private information you have stored on it & using it however they want, installing software to do their bidding instead of yours, & so on. Even if they aren't completely successful, the attack may leave your system unstable or sluggish, destroy some or all of your document files, or even corrupt the file system so badly that you would have to erase everything & start fresh with a new installation of the OS to recover.
With just one user who has unrestricted access to control everything, that isn't very hard to do. To prevent this (& to prevent users from accidentally doing things with the same result), like in every other modern OS, OS X includes a complex system of permissions to restrict & control access to various parts of the system. In OS X, this is implemented as an abstracted system of users & groups, each given permissions to perform only specific kinds of tasks.
So for example, when a human user like you or me asks the Mac to do something, that request may be handed off to one or more non-human users, each able to handle only part of that task, & relying (like us) on other non-human users to do what it can't.
This compartmentalization makes it very difficult to take over control of the Mac & force it to do things it should not do, whether by accident or intent. It also makes it difficult to understand exactly how it all works. Fortunately, as has already been said, as users we don't need to unless we are intent on changing it. And if we are going to do that, we better have a very good understanding of how it all works. (Otherwise, it is very likely we will just break things, cause data loss, or worse.)
If understanding all that is your goal, Apple's developer web site is full of info you can study, & there are quite a few books on the subject. But be warned, this is not simple stuff. It can take months or years to absorb it all.
That's why most of us leave it to the programmers & just use our Macs to do the stuff we want without worrying too much about how it does that.