3. Run Python Script¶

3.1. Run Python¶

To run a script in python, just type python script.py , then our program will compile and run at the same time

Note

In fact, python use a program, called the interpreter (/usr/bin/python in Linux or python.exe in Window) to compile our source code to the bytecode *.pyc, then execute this bytecode.

3.2. Python Interactive¶

The Python interpreter is usually installed at the path of python installation. To open this, juste typing python to the shell, we have :

$ python
Python 2.7.9 (default, Mar  1 2015, 12:57:24)
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

and from now, we can apply and test all python commands here !!

Tip

For me, this tool is very important on my work. When I write a new function, always I test it directly on Interactive Console with maximum testcase possible. This way helps me avoid many stupid mistakes.

3.3. Python command options¶

We mostly use python -m mymodule to run a python source code . But there are other common command-lines options :

python [-c command | -m module-name | script | - ] [args]

-c

The -c cmd option can be used to execute short programs in the form of a command-line option—for example:

$ python -c "print('hello world')".
hello world

-m

Runs a library module as a script which executes inside the __main__ module prior to the execution of the main script. For this command, example python -m mymodule : Python does 2 things :

First, import the packages mymodule. If the given module isn’t located on the Python module path, an error is handled here and the program will be stop.

Second, run this module mymodule like as a script.

Exemple : I have a script foo.py

print 'hello'
print __name__

then we run this script by 2 ways:

$ python foo.py
hello
__main__
$ python -m foo
hello

We have the same result ! Attention with the path to our module, it raise an error if the module isn’t in the PYTHON_PATH.We shall see it at sys module