Managing file permissions.

Discussion in 'macOS' started by applesupergeek, Jan 1, 2010.

  1. applesupergeek macrumors 6502a

    Nov 20, 2009
    Hey guys, I haven't given the appropriate time to understand permissions in OS X, and I 've been having some issues with it, I am decently versed in unix so I supposed I had pretty much understood permission issues. But I have been having problems copying files between my macs, permissions problems.

    As far as I can understand I need to set a uniform user name across my macs (I am not sure how I can change my current user name, can i?), is that correct? Hence all the files will have permissions for a set user, myself and won't have any issues.

    But what about a friends mac? Do you set permissions to everyone so that you can transfer files and not have a problem viewing the, or someone else.

    I ve also found it hard to just select a folder and have all the subfolders change permissions.

  2. maflynn Moderator


    Staff Member

    May 3, 2009
    I've very rarely needed to adjust the permissions on any files with OSX but if you feel the need, then just use the chown command to correct the permission issue.
  3. applesupergeek thread starter macrumors 6502a

    Nov 20, 2009
    yeah that's the strange thing, why I am having these issues, while people tell me they haven't experienced any of this...strange really... next time it happens I ll be more attuned to note the exact problem, what file, when, how...

    Thanks for that command! I wasn't aware of it. It's supposed to re-own a file right?
  4. chown33 macrumors 604

    Aug 9, 2009
    Sailing beyond the sunset
    No, not really. The user name is irrelevant. The user ID is what counts.

    The value stored as the owner and group of every file or dir on the file-system is a user ID, not a user name. This is completely standard Unix, and always has been. The only thing different now is the size of the IDs has increased.

    Example Terminal commands to see some uid's:

    Show the current user's id and groups, as both numbers (IDs) and names.
    List the current user's home folder, showing owner and group as names.
    ls -l ~
    List the current user's home folder, showing owner and group as numbers (IDs).
    ls -ln ~
  5. applesupergeek thread starter macrumors 6502a

    Nov 20, 2009
    Thanks for clearing this up, what I don't understand with the id system, is that if you are a first user on the mac you get a 501, then you transfer a file to another mac with a single user account, and the files there too are uid 501, so what's there to distinguish any of them from one another? What's the point of an id that is uniform and meaningful only on one system but completely irrelevant on another.... legacy unix stuff I guess...

    p.s. and for some strange reason despite having only one user account, I am 502 on my imac...strange.

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