Why different behaviors between running Python module as an executable vs. Python [filename]

Question

So, I created a simple python module, test.py

import commands

def main():
  cmd = 'ls -l'
  (status, output) = commands.getstatusoutput(cmd)
  print status, output

if __name__ == '__main__':
  main()

When I ran it using "Python test.py", I got the result that I expected. But when I ran it as an executable (yes, it has the 'x' permission), the program didn't respond at all and I had to Ctrl+C to quit it. Why is that? Shouldn't both ways give the same result?

Is #!/usr/bin/python the first line of your script? If in windows it should be something like #!C:\[python_dir]\python.exe I think. — krs1
– krs1, Commented May 3, 2011 at 18:45

John Kugelman · Accepted Answer · 2011-05-03 18:46:49Z

6

Add a hash-bang line to the top:

#!/usr/bin/env python

import commands
...

This tells your system what interpreter to use to execute the script. Without it it doesn't know if it's a shell script, Perl script, Python script, what.

answered May 3, 2011 at 18:46

John Kugelman

365k70 gold badges555 silver badges600 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

voithos · Accepted Answer · 2011-05-03 18:48:37Z

2

You need the hashbang to be the first line of your script, referencing the path of the Python interpreter. Otherwise, all the OS knows is that you're trying to execute a script, and it has no idea how to go about doing that.

answered May 3, 2011 at 18:48

voithos

70.9k12 gold badges107 silver badges120 bronze badges

1 Comment

poke Over a year ago

in fact it doesn't even know that it is a script. It could be any kind of thing that is executable.

Collectives™ on Stack Overflow

Why different behaviors between running Python module as an executable vs. Python [filename]

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related