What is Lock folder doing ?

Question

I would like to lock a folder so that I can open the folder and the documents inside it but not alter anything
If you Ctr Click the folder , then press Get Info, you can lock the folder
But what is it doing ?
I noticed that I could not add new files to the folder. That is all.
I do not want to used complicated procedures such as with Disk Utilities

Answer 1

Bomiboll wrote:
Yes sir. That's the situation. I can edit it, I can save it, and to the same place.
It means that this is a flaw in Mac OS.
No, it just means you don't understan Posix permissions and the Access Control Entries.
Locking a folder doesn't do anything but Lock the folder. Access to the contents are still controlled by the Posix permissions and the ACEs. Setting a folder to Locked in Get Info sets the uchg flag. That will prevent you from changing the Folder, but not it's contents, which still have the same settings as they had before you Locked the folder. You can override the delete, but you can't rename or move it (which are the same things in unix), or add items into it. If you want to lock all the files inside, you have to select them all and lock them.
Using the shell,
chflags -R uchg /Users/username/Documents/My\ Locked\ Folder/
In unix, a folder is really nothing but a part of the full name of the file. E.g.
/Users/username/Documents/My\ Locked\ Folder/myFile.txt
A better way to achieve what you want is to set it to Read Only for User, Group, and Others
In the Finder, Get Info on the folder and unlock the padlock on the Permissions section.
Set yourself to read only.
Set the group(s) and everyone to no more than Read Only.
Cick the Gear icon and choose Apply to Enclosed.
In the shell,
chmod -R -w /Users/username/Documents/My\ Locked\ Folder/
The uappend flag is more like what you want. It allows adding to the folder, but not editing the contents.
So, you could lock the folder and set it to not let you change the contents at all with:
chflags uchg,uappend /Users/username/Documents/My\ Locked\ Folder/
However, some programs will allow you to authenticate to make changes to the files, even with those settings.
Then there's Access Control Lists which further add to the complexity. This help page for Tinker Tool System is a brief introduction. If you search for OS X ACL you will find lots of articles on how to set them.