[SOLVED] Python: Using strings to run commands in os.system('')

MetaMan · 06-20-2011, 07:24 PM

I was zsync-ing the latest Ubuntu 11.10 Alpha and thought I'd make a little GUI for it as a small project. The gui is set up, I just need to figure out how to run zsync with content from to variables, cto and cfrom. I tried the following code:

Code:

os.system('zsync -i ' + cto + ' ' + cfrom)

which gives me the error:

Code:

Traceback (most recent call last):
  File "zsync.py", line 45, in start_button_clicked
    os.system('zsync -i ' + cto + ' ' + cfrom)
TypeError: cannot concatenate 'str' and 'builtin_function_or_method' objects

Does anyone know how to fix this?

Thanks!

indienick · 06-20-2011, 08:24 PM

Maybe try using formatting directives:

Code:

os.system('zsync -i {0} {1}'.format(cto, cfrom))

grail · 06-20-2011, 09:16 PM

What if you concatenate into a single string and pass that to os.system()?

MetaMan · 06-20-2011, 09:42 PM

Wait a minute, it must be an issue with how I'm assigning text to variables...

This is wrong, it't it:

Code:

cto = self.copy_to.get_text
cfrom = self.copy_from.get_text

ntubski · 06-20-2011, 10:23 PM

I guess get_text is a function, so you have to call it to get the text:

Code:

cto = self.copy_to.get_text()

Also, I would recommend using the subprocess module functions to pass the parameters separately, that way even if the arguments have spaces or other special characters in them, you won't get weird behaviour:

Code:

subprocess.call(['zsync', '-i', cto, cfrom])