Python subprocess readlines()?

Question

So I'm trying to move away from os.popen to subprocess.popen as recommended by the user guide. The only trouble I'm having is I can't seem to find a way of making readlines() work.

So I used to be able to do

list = os.popen('ls -l').readlines()

But I can't do

list = subprocess.Popen(['ls','-l']).readlines()

Answer 1

ls = subprocess.Popen(['ls','-l'], stdout=subprocess.PIPE)
out = ls.stdout.readlines()

or, if you want to read line-by-line (maybe the other process is more intensive than ls):

for ln in ls.stdout:
    # whatever

Answer 2

With subprocess.Popen, use communicate to read and write data:

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

Then you can always split the string from the processes' stdout with splitlines().

out = out.splitlines()