I imagine there's relatives like the programmer beard, but googling "UNIX beard" returns some examples where it seems to be a thing.

http://www.usenix.org.uk/content/unix_beards.html

https://www.urbandictionary.com/define.php?term=Unix%20beard

https://www.reddit.com/r/linux/comments/4nt38v/how_many_of_you_have_a_unix_beard/

https://www.atlasobscura.com/articles/why-do-hackers-love-beards-so-much subtitle: " Decoding the “Unix beard” at this year’s DefCon.

https://pthree.org/2009/11/01/get-your-unix-beard-on/

 Tyler

On Fri, Dec 18, 2020 at 3:56 PM Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:

    > From: Tyler Adams

    > We all know and love the UNIX beard, but I can't find anything on how
    > the beards started other than an old photo of Ken and Dennis

I'm not sure the term is Unix-specific. At a fairly early stage, people who
worked on the ARPANET/Internet (when PDP-10's were still the 'usual' host, and
Unix systems were just starting to beceome common) were jokingly known as
'network grey-beards': the prototypical one being Jon Postel. (Vint Verf's
beard was too tidy to qualify, IIRC!)

      Noel