pipe large amount of data to stdin while using subprocess.Popen

Question

I\'m kind of struggling to understand what is the python way of solving this simple problem.

My problem is quite simple. If you use the follwing code it will hang. T

Answer 1

Here is an example (Python 3) of reading one record at a time from gzip using a pipe:

cmd = 'gzip -dc compressed_file.gz'
pipe = Popen(cmd, stdout=PIPE).stdout

for line in pipe:
    print(":", line.decode(), end="")

I know there is a standard module for that, it is just meant as an example. You can read the whole output in one go (like shell back-ticks) using the communicate method, but obviously you hav eto be careful of memory size.

Here is an example (Python 3 again) of writing records to the lp(1) program on Linux:

cmd = 'lp -'
proc = Popen(cmd, stdin=PIPE)
proc.communicate(some_data.encode())