I don't know where I would have used CentOS (I'd guess bash is the default interactive shell, but I don't know for sure).
Most people in Linux classes would use Putty on Windows to log into the school machine. I installed Linux Mint, other's used bash on Mac OS X, and I know of one guy who ran Arch. That puts us slightly ahead of the curve.
So I know local bash commands. I know enough make to compile my c code with a Makefile that I copy and modify. As
I have to look up ssh and rsync options. When would I, as a student, really be doing stuff across linux machines? I have picked up a bit of bash scripting (helped by the fact that I learned perl, and perl is closer to bash then you would think), but that's less than usual. Most people who know Python script in python and so on, and may ignore linux commands and pipelining in favor of their preferred language's built in's.
The Zend thing is a little weird, but most people going into entry level jobs expect to learn the specific framework on the job. Hell sometimes the specific language. I don't know if I would list Zend on my resume if I had only that guy's experience, but a course in OO PHP is pretty specific for a college course. Unless Zend is driving PHP usage like Rails did for Ruby, The guy expected to be able to demonstrate the capacity to learn it and understanding of the underpinnings (PHP and OO), not actually how to do it. Apparently that guy got an interview, and more modest people probably didn't.
I certainly list Perl and will say I can do OO Perl code, but I have never used Moose, just old fashioned blessed hashes.
At entry level, you should hire the person, not the skills. Have they written code for something outside of a school project? Have they written code for their personal use? Are they still learning? Can they articulate their understandings of relevant concepts clearly? Can they program something in their preferred language and one or two more to show the ability to generalize?
A good entry level candidate can do most (but not necessarily all) of the above.
Entry is about talents, not skills, and that's what you should be looking for.
Maybe my expectations aren't par for the course where you are, but remember that the best candidates, the guys who have been programming since they were 8 and write their own lisp compilers, they have jobs lined up before they graduate.
You can always contact professors at local schools who teach classes relevant to your job openings, and ask them what gets a good grade, and what is an average grade.
Calibrate your expectations. Expect people who aren't qualified will try to get the interview anyway. Expect that people won't know as much as you, or even as much as you did when you were just graduated.