Miscellaneous Commands

!                         -- system call
?                         -- list commands 
??                        -- list variables 
echo                      -- type this line 
exec                      -- system call
exit                      -- exit program 
help                      -- get help on a function 
output                    -- redirect output to file
quit                      -- exit program 
scan                      -- scan line from keyboard or file to variable 
wait                      -- wait until return is typed
which                     -- show command

Most of these are self-explanatory. The command ?? prints the system variables. The help command will provide help on a single command or, without any arguments, will list all available help files (this includes general help not associated with a specific command).