Programmatically change the shell's cwd in a portable way

Question

I\'d like to write a command line tool in C that acts as an advanced \"cd\" or \"pushd/popd\" command that can be ported to Windows/Mac/Linux. (Full details, in case you are cur

Answer 1

$(echo "cd /foo/bar")

That demonstrates how you might do such a thing with a POSIX shell. It's not portable with the Windows shell, of course.