`#!/bin/sh' makes this less portable than it could be, if /bin/sh doesn't exists on my system it won't work, for example. Remove that line and it'll work everywhere.
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.