If you just installed some OpenSource packege and your shell cannot run this program.
You can do it by specifying full path to this program
/QOpenSys/pkgs/bin/mc
or you can create symbolic link into your bin directory
ln -s /QOpenSys/pkgs/bin/mc
or you can add path to pkgs directory into your PATH variable
PATH=/QOpenSys/pkgs/bin:$PATH
export PATH
To make PATH change permanently you can add this command to your .profile file located in /home/my_user_name/.profile
if this file doesn't exist you can create it by
touch /home/my_user_name/.profile