Using the MANPATH environment variable, you can select which man page directories are searched when using man or apropos. This recipe describes changing your MANPATH variable when using the Bourne shell.
If you have added software with its own man page directory, such as /usr/local/software/man, you can add this to your personal MANPATH variable so that those man pages will be available to man. The technique for changing this variable depends on your shell.
If you are using the Bourne shell (sh), you must edit the file .profile in your home directory (You can use the shortcut ~/.profile to refer to this.). If this file already contains a MANPATH declaration, you can add the new path by adding:
:/usr/local/software/man
to the end of the line so that it looks something like the following:
MANPATH=/usr/man:/usr/local/man:/usr/local/software/man
If your Bourne shell .profile doesn’t have a MANPATH directive, you can create one by adding these lines to .profile:
MANPATH=/usr/local/software/man
export MANPATH