I’m a little behind on putting up my recent Mac articles for TechRepublic here, so I’m going to put them all in one post.
The first is Introduction to OS X Access Control Lists (ACLs) which introduces you to OS X's implementation of filesystem access control lists. OS X, like Linux, has ACLs that can be used to secure files beyond standard owner/group/world permissions. While the Finder lets you manipulate ACLs a little bit, the CLI tools are much more extensive.
The second is Finding hidden commands with the Option key which looks at some tricks hidden in OS X that are available just by holding down the Option key. There are some neat little nuggets you can expose when holding down that Option key and clicking on things, and this tip illustrates a few.