$ ./prog
No such command: 

Available commands:
  hello
  help

$ ./prog help

hello <firstname> <lastname> 
  Displays a friendly hello

help <command> <showsource> 
  Shows help information for a command

$ ./prog hello Jeff Lindsay
Hello, Jeff Lindsay.

$ ./prog help hello
hello <firstname> <lastname> 
  Displays a friendly hello

cmd-hello () 
{ 
    declare desc="Displays a friendly hello";
    declare firstname="$1" lastname="$2";
    echo "Hello, $firstname $lastname."
}