First of all, you are cutting out the middleman; subprocess.call by default avoids spawning a shell that examines your command, and directly spawns the requested process. This is important because, besides the efficiency side of the matter, you don’t have much control over the default shell behavior, and it actually typically works against you regarding … Read more
os.system() returns the (encoded) process exit value. 0 means success: On Unix, the return value is the exit status of the process encoded in the format specified for wait(). Note that POSIX does not specify the meaning of the return value of the C system() function, so the return value of the Python function is … Read more
Avoid os.system() by all means, and use subprocess instead: with open(os.devnull, ‘wb’) as devnull: subprocess.check_call([‘/etc/init.d/apache2’, ‘restart’], stdout=devnull, stderr=subprocess.STDOUT) This is the subprocess equivalent of the /etc/init.d/apache2 restart &> /dev/null. There is subprocess.DEVNULL on Python 3.3+: #!/usr/bin/env python3 from subprocess import DEVNULL, STDOUT, check_call check_call([‘/etc/init.d/apache2’, ‘restart’], stdout=DEVNULL, stderr=STDOUT)
If you want to have an exception thrown when the command doesn’t exist, you should use subprocess: import subprocess try: subprocess.run([‘wrongcommand’], check = True) except subprocess.CalledProcessError: print (‘wrongcommand does not exist’) Come to think of it, you should probably use subprocess instead of os.system anyway …
What gets returned is the return value of executing this command. What you see in while executing it directly is the output of the command in stdout. That 0 is returned means, there was no error in execution. Use popen etc for capturing the output . Some thing along this line: import subprocess as sub … Read more
If all you need is the stdout output, then take a look at subprocess.check_output(): import subprocess batcmd=”dir” result = subprocess.check_output(batcmd, shell=True) Because you were using os.system(), you’d have to set shell=True to get the same behaviour. You do want to heed the security concerns about passing untrusted arguments to your shell. If you need to … Read more