I wanted to put a calendar in a file so I ran:$ ncal -CMh > file.txtBut instead I received the following:Usage: cal [general options] [-hjy] [[month] year]       cal [general options] [-hj] [-m month] [year]       ncal [general options] [-bhJjpwySM] [-s country_code] [[month] year]       ncal [general options] [-bhJeoSM] [year]General options: [-NC31] [-A months] [-B months]For debug the highlighting: [-H yyyy-mm-dd] [-d yyyy-mm]I was surprised because I was sure the command is correct. I thought perhaps, getopts options are not permutable like I thought so I tried reordering the options. However all permutations that didn't have -C before -M worked:$ ncal -hC$ ncal -Ch$ ncal -hM$ ncal -Mh$ ncal -MCh$ ncal -MhC$ ncal -hMC$ ...My theory is that when ncal enters cal mode using -C it loses the -M option probably because -M didn't exist in original cal. I have no idea if this is correct or not.Why does this happen?This is on latest Debian Jessie.
Why is that `ncal -CM` doesn't work but `ncal -MC` does?
shell;cal