so what the heck are permissions?

[27 houdini's]

so what the heck are permissions and why do want to repair them anyway (an option in the disk utilities app)?

 

[bobw]

From Apple's TIL #106712

Permissions Defined

Mac OS X incorporates a subsystem based on a UNIX-style operating system that uses permissions in the file system. Every file and folder on your hard disk has an associated set of permissions that determines who can read, write to, or execute it. Using the AppleWorks application and one of its documents as an example, this is what the permissions mean:

Read (r--)
You can open an AppleWorks document if you have the read permission for it.
Write (-w-)
You can save changes to an AppleWorks document if you have the write permission for it.
Execute (--x)
You may open the AppleWorks application if you have the execute permission for it. This permission is only relevant for applications and other types of executable files.

When you can do all three, you have "rwx" permission. Permissions for a folder behave similarly. With read-only permission to a folder containing documents, you can open and read documents but not save changes or add new documents to the folder. Read-only (r--) permission is common for sharing files with guest access, for example.

Go to this page for rest of article;

http://docs.info.apple.com/article.html?artnum=106712

 

[27 houdini's]

sounds pretty logical considering the name. Now i read this part of another post ("the witch is gone" or something like that) about explorer messing up the permissions.
So how does that fit in this story that seems to apply to users and not applications and why do they get messed up anyway?

Thanks