And to elaborate even more: ‘:’ is the command, and ‘$(cal)’ – which equals the unquoted output from running the ‘cal’ command – are the arguments. The last da

And to elaborate even more: ‘:’ is the command, and ‘$(cal)’ – which equals the unquoted output from running the ‘cal’ command – are the arguments. The last day of the month is thus the last argument of ‘:’ and can be referenced with the ‘$_’ variable.