Permissions on files copied from shared computers

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Level 5

6,317 points

Permissions on files copied from shared computers

Whenever I copy a file from my PC to my Mac over the LAN I have observed that the permissions assigned to the file are read and write for the owner which is always the user logged in to the Mac. The other permission shown in the get info window is everyone no access. This is independent of whether the file was a shared file on the PC or a file from 'My Documents' that was not shared. If I look at permissions in Terminal the group staff is shown as one would expect, however staff has no access. Staff does not show up in get info window. Obviously this means that every time I bring a file over from the PC I have to correct the permissions if any other user is to be able to use it when I put it in my public folder.
I would have expected that files copied from the PC ought to have the user as the owner with rwx permissions, staff as group with read only, and everyone as read only. That is not the case.

Also I would like to know how to add the staff group to these files using get info window. I know how to do it with Terminal, but not with the info window. If you go to the permissions section of get info and click the + the window that comes up shows only Administrators as a choice for adding a group. Staff does not appear for example. I know you can add new groups but that seems to require establishing a new account, which doesn't seem appropriate since staff ID already exists.

Any help anyone can offer on this quandary is appreciated. I have lots of pictures copied over from the PC and having to change permissions on them in order to share via public folder is a daunting exercise.

G4 Dual 1.25 MDD, Mac OS X (10.5.2)

Posted on Apr 11, 2008 3:34 PM

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Answer 1

AK_Mike

Level 4

1,233 points

Apr 11, 2008 5:19 PM in response to Jim Wanamaker

When you copy a file you are actually creating a new file by the same name with the same contents. Therefore permissions on the new file will be inherited from the directory it is created in.

So if the file is created in a directory that is shared out and permissions are set so a particular group or the group everyone has read or read/write permissions, you should not need to do any further tweaking.

Now if you move a file from one directory to another the file retains the original permissions it received when created.

A move from one volume to another is actually a copy.

Sometimes you need to pull up the permissions on the enclosing directory and click the button to force the directory permissions on to the contents. However this only works when the owner of the directory invokes it.

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Answer 2

Jim Wanamaker Author

Level 5

6,317 points

Apr 11, 2008 8:04 PM in response to AK_Mike

Thanks AK__Mike for your information. Your explanation is quite clear and informative. Let me give you some additional specifics on what is happening.

The pics reside in 'My Pictures' on my PC running XP. They are organized in sub-directories representing a days shoot. On my Mac I have a sub-Directory within 'Pictures' in my home directory named 'New Pictures'. I log into the PC from the Mac and copy a sub-directory of pics from 'My Pictures' directly into 'New Pictures' on the Mac. On the PC 'My Pictures', all sub-directories, and the pics within the sub-directories all have me as owner and the group everyone has read and execute for sub-directories and read for files within the sub-directories. On the Mac the 'New Pictures' directory has me as owner with full privileges, group staff with read only and everyone read only. What happens is that the sub-directory and enclosed pics that I copy from the PC end up with me as owner with full privileges and everyone with no access. No group is shown in get info panel. However if I check in Terminal I see the group staff, but it has no access.

This is all very convoluted but the point is that the pics can only be read by owner which stays that way if you drop them into the public folder. Other users can not open them or even see a thumbnail just a generic JPEG icon. Any additional thoughts would be appreciated. It is interesting that get info shows no group while Terminal does.

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