I am trying to understand
info who but completly fail at the term "non-option argument". Can someone please explain this term to me in simple words or an example?
info who :
If given no non-option arguments,
whoprints the following information for each user currently logged on: login name, terminal line, login time, and remote hostname or X display.
If given one non-option argument,
whouses that instead of a default system-maintained file (often
/etc/utmp) as the name of the file containing the record of users logged on.
/var/log/wtmpis commonly given as an argument to
whoto look at who has previously logged on.
If given two non-option arguments,
whoprints only the entry for the user running it (determined from its standard input), preceded by the hostname. Traditionally, the two arguments given are
am i, as in
who am i.
I [thought to] know the difference between an argument and an option, but this [again] nixes a lot.