Python Hello World Example: How To Write and Execute Python Program on Unix OS

Question: I would like to understand the basics of how to write and execute a python program on Linux OS. Can you explain it with a simple example?

Answer: In this article, let us review very quickly how to write a basic Hello World python program and execute *.py program on Linux or Unix OS.

1. Write a Hello World Python Program

Create helloworld.py program as shown below.

$ vim helloworld.py

#!/usr/bin/python

# Hello world python program

print "Hello World!";

2. Verify Python Interpreter Availability

Make sure python interpreter is installed on your system as shown below.

$ whereis python
python: /usr/bin/python /usr/bin/python2.5 /usr/bin/python2.6 /etc/python
/etc/python2.5 /etc/python2.6 /usr/lib/python2.4 /usr/lib/python3.0
/usr/lib/python2.5 /usr/lib/python2.6 /usr/local/lib/python2.5
/usr/local/lib/python2.6 /usr/include/python2.5 /usr/include/python2.6
/usr/share/python /usr/share/man/man1/python.1.gz

$ which python
/usr/bin/python

3. Execute Python Program

You can either execute using “python helloworld.py” or “./helloworld.py”.

$ python helloworld.py
Hello World!

( or )

$ chmod u+x helloworld.py

$ ./helloworld.py
Hello World!

Note: As python is an interpreted language, you don’t have the compilation step similar to the C program.

4. Python one liner

You can also execute python from the command line as shown below. This will print Hello World!.

$ python -c 'print "Hello World!"'

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