I'd say "aware" and "familiar with" are two totally different groups. And while I'd agree that "aware" seems like it'd approach 100% of the general programmer pop., from my experience "familiar with" is a surprisingly and saddeningly lower than 100% percentage.
It takes literally 10 seconds to run `ls -la` and `cat` some files to get the information. If that's a problem for an applicant, it's a good exclusion to the funnel.
Like sibling says, on mobile it's a pain. In general, when I look at a job posting, I just want to skim it. I don't want to interact with the webpage in any other way than "reading".
I get it, this is clever. It supposedly weeds out poor applicants. But speaking for myself it just strikes me as annoying.
Do people really apply for jobs on mobile? If I came across it on mobile, I'd just go, oh okay, and read it later on my laptop or desktop.
I'm an admitted anti-mobile person though. I am exceptionally skeptical that the mobile revolution will adequately replace the keyboard/mouse combination for high productivity tasks, and don't wish to see design move entirely in that direction.
Actually, grepping necessary information from the files is more efficient than reading a bloated web page from job site with infinite scrolling where your Ctrl + F is not working.