If you want POSIX compliant, better to install a proper vi. Normal Vim is extremely not POSIX compliant, and I wager 100.00% (rounded to the significant digits

If you want POSIX compliant, better to install a proper vi. Normal Vim is extremely not POSIX compliant, and I wager 100.00% (rounded to the significant digits) of Vim users don't know, use, or want POSIX compliance. You lose a lot of features you would consider to be basic. Also you probably want ed (the standard text editor) for POSIX compliance. (Fun fact, vi is not required by POSIX, so you will not find it on every single POSIX compliant host.)