I'm trying:
import commands
print commands.getoutput("ps -u 0")
But it doesn't work on os x. os instead of commands gives the same output: USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
nothing more
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6 Answers
This works on Mac OS X 10.5.5. Note the capital -U option. Perhaps that's been your problem.
import subprocess
ps = subprocess.Popen("ps -U 0", shell=True, stdout=subprocess.PIPE)
print ps.stdout.read()
ps.stdout.close()
ps.wait()
Here's the Python version
Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53)
[GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin
1 Comment
slacy
This isn't going to be very cross-platform. ps options on Linux/Unix are going to be different, and not exist at all on Windows.
If the OS support the /proc fs you can do:
>>> import os
>>> pids = [int(x) for x in os.listdir('/proc') if x.isdigit()]
>>> pids
[1, 2, 3, 6, 7, 9, 11, 12, 13, 15, ... 9406, 9414, 9428, 9444]
>>>
A cross-platform solution (linux, freebsd, osx, windows) is by using psutil:
>>> import psutil
>>> psutil.pids()
[1, 2, 3, 6, 7, 9, 11, 12, 13, 15, ... 9406, 9414, 9428, 9444]
>>>
Comments
The cross-platform replacement for commands is subprocess. See the subprocess module documentation. The 'Replacing older modules' section includes how to get output from a command.
Of course, you still have to pass the right arguments to 'ps' for the platform you're on. Python can't help you with that, and though I've seen occasional mention of third-party libraries that try to do this, they usually only work on a few systems (like strictly SysV style, strictly BSD style, or just systems with /proc.)
Comments
any of the above python calls - but try 'pgrep
Comments
I've tried in on OS X (10.5.5) and seems to work just fine:
print commands.getoutput("ps -u 0")
UID PID TTY TIME CMD
0 1 ?? 0:01.62 /sbin/launchd
0 10 ?? 0:00.57 /usr/libexec/kextd
etc.
Python 2.5.1
Comments
It works if you use os instead of commands:
import os
print os.system("ps -u 0")
1 Comment
Thomas Wouters
os.system() doesn't give you the output, the output is just printed to the screen. os.system() returns the process exit status, which you'll see as a trailing '0' in the output.