how to run python in terminal

# Save the script in a file with .py extension
# run the script using the below command
python fileName.py

#For Python 3:
$ python3 helloworld.py
#For Python 2:
$ python helloworld.py

exec(open('file.py').read())

#By Uku Loskit

import os
os.system("ls -l")

import sys
if sys.stdin.isatty():
    # running interactively
    print "running interactively"
else:
    with open('output','w') as f:
        f.write("running in the background!\n")

# press [windows] + [R] (on windows only)
# use the command : cd/the_way_of_your_program
# and now use this command :

py the_name_of_your_program.py 

# don't forget to write the extension (py for python) 
# at the end of your program name