[mpich-discuss] man mpich-3.0.4

How do I set the MANPATH mpich-3.0.4 on Debian Wheezy? The installation location is /opt/mpich. I tried in ~/.bashrc: MANPATH = /opt/mpich/share/man:$MANPATH export MANPATH but not work. I call 'man mpich', or is not that what you call the man of mpich? I researched and not found. However, PATH=/opt/mpich/bin:$PATH export PATH worked.