Replace `echo -e` with `printf`
    
    This script uses `#!/bin/sh` as its shebang, which means it expects a
    POSIX-compliant shell. However, it also uses `echo -e` which is not
    POSIX-compliant[0].
    
    Rewrite `echo -e "$arg"` invocations to `printf "$arg\\n"` so that
    the script is brought into POSIX compliance.
    
    [0]: https://pubs.opengroup.org/onlinepubs/009604599/utilities/echo.html
    [1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/printf.html