Add help

main.py

@@ -15,11 +15,22 @@ def grabArgument(fullCommand, commandRan):
 try:
     while True:
         command = input(currentDirectory + " > ")
-        if command == "pwd":
+        if command == "help":
+            print("This is Mash, Max's Shell. Mash has a few built in commands, which you can use to run commands, view files and interact with your system.")
+            print("Some commands you can run:")
+            print("")
+            print("pwd      Print directory you are currently in")
+            print("cd       Change your directory.")
+            print("cat      View contents of a file.")
+            print("version  Print current version of Mash.")
+            print("exit     Exit Mash.")
+            print("")
+            print("You can also run commands installed by your system. See your OS's documentation for more information.")
+        elif command == "pwd":
             print(currentDirectory)
-        if command == "exit":
+        elif command == "exit":
             exit()
-        if command == "cd":
+        elif command == "cd":
             try:
                 cdDirectory = input("Directory: ")
                 if cdDirectory[0] == "/":