CODEWITHSUNDEEP
pythonbasherror-handlingsystemsubprocess
tkbx
tkbx

Reputation: 16305

Python: os.system() without return or error

I need to use os.system() a few times in my script, but I don't want errors from the shell to appear in my script's window. Is there a way to do this? I guess it's sort of like silent commands, running to their full extent, but not returning any text. I can't use 'try', because it's not a Python error.

Upvotes: 1

Views: 12385

Answers (2)

Eric O. Lebigot
Eric O. Lebigot

Reputation: 94575

The recommended way to call a subprocess and manipulate its standard output and standard error is to use the subprocess module. Here is how you can suppress both the standard output and the standard output:

import subprocess

# New process, connected to the Python interpreter through pipes:
prog = subprocess.Popen('ls', stdout=subprocess.PIPE, stderr=subprocess.PIPE)
prog.communicate()  # Returns (stdoutdata, stderrdata): stdout and stderr are ignored, here
if prog.returncode:
    raise Exception('program returned error code {0}'.format(prog.returncode))

If you want the subprocess to print to standard output, you can simply remove the stdout=….

Upvotes: 2

NPE
NPE

Reputation: 500773

You could redirect the command's standard error away from the terminal. For example:

# without redirect
In [2]: os.system('ls xyz')
ls: cannot access xyz: No such file or directory
Out[2]: 512

# with redirect
In [3]: os.system('ls xyz 2> /dev/null')
Out[3]: 512

P.S. As pointed out by @Spencer Rathbun, the subprocess module should be preferred over os.system(). Among other things, it gives you direct control over the subprocess's stdout and stderr.

Upvotes: 4

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