Τι είναι τα permissions στο Mac OS X:
Permissions
Every file on the system has associated with it a set of permissions. Permissions, in conjunction with owner and group information, tell the operating system what can be done with that file and by whom. There are three things you can (or can't) do with a given file:
read it,
write (modify) it and
execute it.
Permissions specify what the owner, the group, and others can do with the file. For any given entity ('owner', 'group' and 'other'), we need three bits to specify access permissions: the first to denote read (r) access, the second to denote write (w) access and the third to denote execute (x) access. Each entity ('owner', 'group' and 'other') has its own permission triplet. Each bit can be set or clear (not set). We mark a set bit by its corresponding operation letter (r, w, or x) and a clear bit by a dash (-) and put them all on a row. An example might be rwxr-xr-x, where the first three (the first triplet, rwx) indicates the owner can do anything with the file, and the second and third triplets (r-x) indicate the group and the rest of the world (the others) can only read and execute it.
So if you try ls -l (lowercase ell) from a Terminal command prompt you will get something like the following:
[zorlarf:guns] djclark% ls -l
-rwxrwxrwx 1 djclark staff 8449880 Mar 21 2000 November Rain.mp3
drwxrwxrwx 16 djclark staff 500 Jun 21 2001 Illustrations
-rwxrwxrwx 1 djclark staff 3832685 Apr 22 1999 Welcome to the Jungle.mp3
The first column here shows the permission bit pattern for two files and one directory (directories have permissions too, as we'll discuss in a moment). The third column shows the owner to which the file (or directory) belongs, and the fourth column shows the group to which the file (or directory) belongs. By this time, the information provided by ls -l should be enough for you to figure out what each user of the system can do with any of the items shown.
Και όποιο θέλει να εμβαθύνει ας διαβάσει και
αυτό.
