python subprocess output to list or file

Question

I want to run the following bash command in Python 3:

ls -l

I know that I can do the following:

from subprocess import call
call(['ls', '-l'])

How do I save this output to a file, or put it into lists or sets?

[-rw-r--r--]  [1] [name]  [staff]   [426] [14 Jan 21:52] [HelloWorld.class]
[-rw-r--r--@] [1] [name]  [staff]   [107] [14 Jan 21:51] [HelloWorld.java]
...
etc.

I want to be able to access particular information directly, and then add it to the set, but I do not know how many items will be listed.

Any hints, snippets, or examples would really help.

Answer 1

One way to access to the information in ls -l output is to parse it. For example, csv.DictReader could be use to map each column to a field in a dictionary:

import subprocess
import csv

process = subprocess.Popen(['ls', '-l'], stdout=subprocess.PIPE)
stdout, stderr = process.communicate()

reader = csv.DictReader(stdout.decode('ascii').splitlines(),
                        delimiter=' ', skipinitialspace=True,
                        fieldnames=['permissions', 'links',
                                    'owner', 'group', 'size',
                                    'date', 'time', 'name'])

for row in reader:
    print(row)

The code above will print a dictionary for each line in ls -l output such as:

{'group': '<group_name>',
 'name': '<filename>',
 'links': '1',
 'date': '<modified_date>',
 'time': '<modified_time>',
 'owner': '<user_name>',
 'permissions': '-rw-rw-r--',
 'size': '<size>'}