NRPE Works From Command Line; "Incorrect command line arguments" from Nagios
Solution 1:
In conclusion, the issue turned out to be that the dash in the '-H' was not actually a dash. It was an en-dash. You can actually see it quite clearly in the text above if you look for it. Unfortunately, Source Code Pro (the font I use in my terminal, and therefore in vim) does not really differentiate dashes and en dashes. I reopened an issue regarding this, in the meanwhile I'm looking for a new font (and adding dash differentiation to my list of criteria).