Question

I am trying to chmod a folder in OS X Lion

However the settings do not seem to stay when I do…

users-MacBook-Air:MAMP user$ sudo chmod a=rwx /tmp

users-MacBook-Air:MAMP user$ ls -l /tmp
lrwxr-xr-x@ 1 root  wheel  11 Jul 20 23:44 /tmp -> private/tmp

Answer 1

The first letter l in lrwxr-xr-x means that /tmp is a symbolic link.

This part /tmp -> private/tmp means that it links to private/tmp.

From man chmod:

chmod never changes the permissions of symbolic links; the chmod
system call cannot change their permissions. This is not a problem
since the permissions of symbolic links are never used. However,
for each symbolic link listed on the command line, chmod changes
the permissions of the pointed-to file. In contrast, chmod ignores
symbolic links encountered during recursive directory traversals.

So, you can safely ignore your link’s permissions.

Note that private/tmp is a path relative to the folder where /tmp is located – /. Its absolute path is /private/tmp.