The `posix-cd` program

posix-cd changes the current working directory to a given directory, then executes a program.

Interface

     posix-cd [ -L | -P ] dir prog...

posix-cd changes the current working directory to dir according to the POSIX specification for a cd external utility. Then, if prog... is not empty, it execs into it.

When execline has been configured with the --enable-pedantic-posix option, the cd command is a symbolic link to it. So scripts calling cd will use posix-cd. When this configuration option has not been given, cd is a symbolic link to execline-cd.
posix-cd fully conforms to the POSIX specification. When prog... is not empty, the behaviour of a cd utility is not specified by POSIX, so posix-cd extends the spec to be actually useful and usable in an execline program with the same interface as the regular execline cd command.
Nobody ever executes or needs the external version (i.e. not a shell builtin) of the POSIX cd command. Compared to execline's regular cd binary, execline-cd, posix-cd is uselessly bloated and slow. The only reason it exists is that some distributions refuse to package execline correctly unless it is strictly POSIX-compliant; the --enable-pedantic-posix configure option is there to satisfy their requirements.