On Linux and recent FreeBSD, this is how:

cp -al dirA dirB 

For a more portable solution, see answer using pax and cpio by Stéphane Chazelas

On Linux (more precisely with the GNU and busybox implementations of cp as typically found on systems that have Linux as a kernel) and recent FreeBSD, this is how:

cp -al dirA dirB 

For a more portable solution, see answer using pax and cpio by Stéphane Chazelas

This is how:

cp -al dirA dirB 

(Yes, I'm answering my own question)

On Linux and recent FreeBSD, this is how:

cp -al dirA dirB 

For a more portable solution, see answer using pax and cpio by Stéphane Chazelas