> Applications should note that the standard PATH to the shell cannot be assumed to be either /bin/sh or /usr/bin/sh, and should be determined by interrogation of the PATH returned by getconf PATH, ensuring that the returned pathname is an absolute pathname and not a shell built-in.
> Applications should note that the standard PATH to the shell cannot be assumed to be either /bin/sh or /usr/bin/sh, and should be determined by interrogation of the PATH returned by getconf PATH, ensuring that the returned pathname is an absolute pathname and not a shell built-in.
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/s...
However, in my experience, I don't recall seeing any POSIX or POSIX like system that didn't have /bin/sh.