$ module avail
--------------------- /usr/local/modulefiles/Core ----------------------
   gcc/6.2    gcc/7.1    gcc/8.1 (D)    pgi/16.10    pgi/18.4 (D)
---------------- /usr/local/lmod/lmod/modulefiles/Core -----------------
   lmod/6.5    settarg/6.5
  Where:
   D:  Default Module
Use "module spider" to find all possible modules.
Use "module keyword key1 key2 ..." to search for all possible modules
matching any of the "keys".