Newbie Shell Editor Question

[runsun pan]

whatever you type after the >>> is either a statement that command
python to do something (like "print 'hello'"), or an object that might
or might not contain/return a value. The 'hello' you typed (the one
that caused error) is simply a word. It is not a command, it is not a
variable, it is not an object. Compare to this:

>>> print "Hello"
Hello
>>> hello=3   # assign 3 to a variable 'hello'
>>> hello       # Now hello is a variable containing 3
3

when you typed :

>>> hello

python will try to look for any variable named 'hello' in order to
investigate its content for return. But it can't find it because you
didn't define it.