RE: Linux distros, I am familiar with Ubuntu, Debian, and Arch Linux. To some extent RHEL as well.
RE: Unix (commercial brand names), none. It was my fault that I assumed the recruiter meant UNIX-like systems.
I can claim experience with developing userland applications portable across POSIX-compliant systems, as well as some understanding of lower-level operating system concepts. However, to be honest it seems I am unqualified for the role as specified, which makes the exchange all the more embarrassing. Oh well, what's done is done.
The recruiter did mean UNIX-like systems. There exists no useful set of experience which is common among pedantically defined "UNIX" and which excludes UNIX-like systems. The pedantic definition-lawyer type responses you've gotten are absurd.
A role might specifically require extensive AIX experience in particular -- and if it did you would say you needed "AIX experience" -- never some vague umbrella family of "UNIX experience."
It is entirely unbelievable that the requirements for this role would exclude your experience. Doubly so as they're recruiting from interns. Triply so if you know anything about Facebook engineering teams. "Production Engineer?" "Frontend Engineer?" At Facebook? Yeah, those teams run Linux.
ps: The folks telling you not to language lawyer are correct. But your initial assumption that the recruiter had made a dumb mistake was also correct.
The recruiter in this case is a pattern-matching engine with no internal semantics, as a result of Facebook hiring them and training them but not educating them.
Eventually they'll notice that they are only seeing car salesmen with extensive experience in selling brown cars with walnut dashboards, rather than carpenters. [ https://news.ycombinator.com/item?id=15190438 ]
You honestly did nothing wrong. I don't think Facebook is looking for UNIX admins/developers, nor are they going to find any for an internship. CS students with experience in AIX, HP-UX, Solaris, or FreeBSD are exceedingly rare. Solaris and FreeBSD are the only two systems that Facebook would have a chance in hell at finding interns for, and even that's a stretch. AIX and HP-UX are expensive and the licensing is painful.
Getting a little frustrated with resume-screening-by-grep is not at all unreasonable. After the recruit had you play whack-a-mole for three resume revisions, a little bit of snark is to be expected. Don't let people walk over you.
A quick search around the web will tell you that FB probably primarily uses CentOS (with custom built components, I'm sure), so your experience was most likely almost directly what they were looking for.
It would have been pretty simple to tailor your resume in that regard. What I know of PE/SRE type positions at companies like FB and Google is that you are literally working with some Linux flavor nearly all the time unless you are applying for a very niche role.
It is not uncommon to come across open positions that actually do require Unix (not Linux) experience.
For example, American Express has a large deployment of AIX systems and they indeed look for candidates with experience in AIX systems, although I believe someone with experience in another Unix or Unix-like system should also be okay.
But I agree that such openings are usually quite specific about which Unix system they are working with.
This is true, but I would imagine that, if not in the job description, if a really specific kind of Unix experience is required, it would come out in the exchange - and be really OS specific and actually say - True64, AIX, Solaris, etc.
"Unix-like" today means bsd/linux. The recruiter did bad, but recruiters will always do bad.
If its a job you want, don't let a recruiter foible disqualify you, if you can help it.
I am curious. Can you be a little specific and tell us what Linux or Unix experience do you have?
I mean can you specify the Linux distro names and the Unix brand names (AIX, Solaris, etc.) that you have worked with?