Question

Right now, I use subprocess to invocate find which does the job fine, but I am after a pythonic way of doing things.

here’s the current code:

cmd = "find /sys/devices/pci* | grep '/net/' |grep address"
p = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=True)

In the output I receive the following list:

[root@host1 ~]# find /sys/devices/pci* |grep '/net/'|grep 'address'
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:00.0/0000:08:00.0/net/eth0/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:01.0/0000:09:00.0/net/eth1/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:02.0/0000:0a:00.0/net/rename4/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:03.0/0000:0b:00.0/net/eth3/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:04.0/0000:0c:00.0/net/eth4/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:05.0/0000:0d:00.0/net/eth5/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:06.0/0000:0e:00.0/net/eth6/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:07.0/0000:0f:00.0/net/eth7/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:08.0/0000:10:00.0/net/eth8/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:09.0/0000:11:00.0/net/eth9/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:0a.0/0000:12:00.0/net/eth10/address
/sys/devices/pci0000:00/0000:00:07.0/0000:04:00.0/0000:05:00.0/0000:06:00.0/0000:07:0b.0/0000:13:00.0/net/eth11/address

Now, if I do glob.glob('/sys/devices/pci*/*/*/*/*/*/*/net/') I do get a list of directories, and I can even look for the files, but it definitely seems to take longer than find does, even through subprocess. Moreover, the set of results is huge, and I can’t know ahead whether the specific hosts’ architecture will have the same directory structure, so I don’t know how many asterisks to enter in glob.glob().

My question is, how can I repeat the behaviour the simple find | grep command achieves, or, alternatively, if there is a nicer way of finding all the MACs of all the NICs a host has, whether active or not (I’m looking for specific MAC patterns here)

EDIT: Shouldn’t have used glob, os.walk seems to be doing the job:

>>> for root, dirs, names in os.walk('/sys/devices/'):
...     if 'address' in names and 'pci' in root:
...         f = open(str(root + '/address'), 'r')
...         mac = f.readlines()[0].strip()
...         f.close()
...         print mac
...         eth = root.split('/')[-1]
...         print eth

Answer 1

Have you checked out os.walk()?

import os
for root, dirs, names in os.walk(path):
    ...

http://docs.python.org/library/os.html#os.walk

From the above link, here is a way to skip over certain directories:

import os
from os.path import join, getsize
for root, dirs, files in os.walk('python/Lib/email'):
    print root, "consumes",
    print sum(getsize(join(root, name)) for name in files),
    print "bytes in", len(files), "non-directory files"
    if 'CVS' in dirs:
        dirs.remove('CVS')  # don't visit CVS directories