How to validly add linux command option at the end?

I am wondering how I can add linux command option at the end without error.

For example

rm file1/ -r

cp file1/ file2/ -r

I experience some Linux cluster system can do it, bus others cannot.

As searched for while, getopts command may help but I am not sure if getopts is best choice for that and (also not sure how to implement for that my purpose).

Do I need to customize command by command or there is more general solution that can be applied any command?

Thank you for your help.

Answer

Consider this command:

rm -f myfile -r -- -i

The GNU flag convention is to allow options anywhere, up until an optional -- to indicate “end of options”. Programs following it will see the options -r and -f, plus the arguments myfile and -i

The BSD flag convention is that flags are only allowed up until the first non-flag argument, or until an optional --. Programs following it will see the option -f, plus the arguments myfile, -r, -- and -i.

POSIX only requires utilities to support the BSD style.

It’s up to the individual program to decide how to interpret flags. If you’re on a BSD style system like FreeBSD or macOS, you can install GNU tools and use those. If you can’t, you’re mostly stuck with the system’s flag convention.