Python Regex re.search to list

Question

I have some code to parse the linux 'df -h', the normal command line output looks like this:

Filesystem      Size  Used Avail Use% Mounted on
udev            987M     0  987M   0% /dev
tmpfs           201M  9.2M  191M   5% /run
/dev/sda1        38G   11G   25G  30% /
tmpfs          1001M  416K 1000M   1% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs          1001M     0 1001M   0% /sys/fs/cgroup
tmpfs           201M   28K  201M   1% /run/user/132
tmpfs           201M   28K  201M   1% /run/user/0

Currently my code achieves the desired output:

['/run', '/run/lock', '/run/user/132', '/run/user/0']

But the 'print ([x.split(" ")[-1] for x in newlist])' line shown below feels like a hack, I'm struggling to get this working as a regex using 'r.search' below, can anyone advise a better way of doing this please ?

import subprocess
import re


cmd = 'df -h'
output = subprocess.check_output(cmd, shell=True).decode('utf8')
ln = output.split('\n')
r = re.compile('/run.*')
newlist = list(filter(r.search, ln))

print ([x.split(" ")[-1] for x in newlist])

Edit * I am using 'df -h' as some random output to practice regex on, so while @romanPerekhrest offers the best real world solution for this problem I was looking for a regex solution.

Actually I believe your solution is better than regexp (and almost certainly faster). — Błotosmętek
– Błotosmętek, Commented Jul 11, 2017 at 15:23

RomanPerekhrest · Accepted Answer · 2017-07-11 15:34:21Z

3

The fastest approach:

df -h --output=target | grep '/run.*'

The output:

/run
/run/lock
/run/user/132
/run/user/0

--output=target - to output only mount points

answered Jul 11, 2017 at 15:34

RomanPerekhrest

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4 Comments

biscuitlover Over a year ago

thanks for this, however I am using the 'df' tool as practice for parsing cmd output in python

RomanPerekhrest Over a year ago

@biscuitlover, it's simple: if you want to stay at Python, your current script would be simplified to

cmd = "df -h --output=target | grep '/run.*'" output = subprocess.check_output(cmd, shell=True).decode('utf8') lines = output.split('\n')

biscuitlover Over a year ago

this is the better real world solution, but i was using 'df -h' as some random output to perform regex on, I should have put that in my original question, thanks again.

RomanPerekhrest Over a year ago

@biscuitlover, yes, I tend to suggest a REAL solutions

Stael · Accepted Answer · 2017-07-11 15:32:55Z

2

how about

re.findall(r'/run.*$', output, re.MULTILINE)

I don't know about better or speed, but it cuts your code down to 3 lines, and you're regexing anyway.

answered Jul 11, 2017 at 15:32

Stael

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3 Comments

biscuitlover Over a year ago

thanks for this, this is exactly what i wanted to achieve !

Stael Over a year ago

to be fair though, the one by @romanPerekhrest is objectively better.

biscuitlover Over a year ago

indeed, I have made an edit to my original question for clarification.

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