GRASS: INHERITED SYSTEM, NEED HELP

[Duane Donnelly-Morrison]

     Dear Grass Users:
     
     I've inherited a GRASS setup that has me baffled, and leaves me unable 
     to enter the GRASS program.
     
     I'm running a SunSPARC Solaris 1.X machine.  I have three GRASS 
     related directories under the /home directory: /home/grass; 
     /home/grass3.1; and /home/grass4.0.  
     
     When I change directory to each of these directories and issue the 
     following commands -- grass; grass3.1; grass4.0 -- I get the "command 
     not found" reply.  When I issue the command -- grass4 -- in the 
     /home/grass3.1 directory, I get the reply "permission denied", but 
     find that there exists an ascii file named grass4 under the 
     /home/grass3.1 directory that has nothing to do with system startup.
     
     Just a little lost here.  How do I get into this program?
     
     Thank you in advance for any suggestions.
     
     Yours.
     
     Duane Donnelly-Morrison
     Email: duane_donnelly-morrison at nps.gov