So maybe
maya.exe -command python("import myScript")
will work for you, but it's better to create and call your functions.
Also, if you want to use the pythonScripts script that is in the
devkit/other/PyQt... to build a menu inside Maya with access to your
pythonScripts,
You should name your main function the same as your script (like MEL)
so you might be invoking.
maya.exe -command python("import myScript;myScript.myScript()")