Let's see if we installed Python successfully!
First check if your virtual environment is active. (You should see
in the beginning of your command line.)
If it's there, we can now start Python (specifically, the Python console).
To do that, just write
(myenv)$ python Python 3.4.0 (default, Jan 26 2014, 18:15:05) [GCC 4.8.2 20131212 (Red Hat 4.8.2-7)] on linux Type "help", "copyright", "credits" or "license" for more information. >>>
This command will print some information.
in the first line, it shows which version of Python you have
(you should have Python 3).
The command line starts with three "greater than" signs.
This way Python prompts (asks) you for instructions.
This is the same as the standard command line, but instead of commands
mkdir, you write Python commands.
The simplest command is a number. Try it:
>>> 1 1 >>> 42 42 >>> -8.3 # (Python uses period as decimal point) -8.3
Python prints the greater-than signs
>>> and the answer by itself!
You just write number and press Enter.
Python can also add up numbers, like this:
>>> 8 + 2 10
Notice that commands from the standard command line do not work here, although the window looks the same:
>>> whoami Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'whoami' is not defined
This is an error message which appears every time when you do anything wrong. You will see a lot of them during the course, so look at it carefully so you recognise it later.
If you got this far, congratulations!
You have installed Python and it works.
You can now quit the Python console and close the command prompt.
To quit, just type
quit() with empty parentheses.
>>> quit() (myenv)$
The greater-than signs
>>> change back to
Now commands like
cd work again, but Python
1 + 2 don't wotk, until you enter the Python console
To quit the virtual environment, type
(for Linux and Mac) -- this time without parentheses.
The command prompt (terminal) can be closed by typing
As an exercise, try to run the Python console again -- open the command prompt (the terminal), then activate the virtual environment, and finally run Python.