I want to run my command and capture stdout realtime:
import subprocess
import shlex
cmd='my command'
args=shlex.split(cmd)
com=subprocess.Popen(args,stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
com.stdout.flush()
for line in com.stdout.read()
print line
But there is nothing as output...
read() reads until EOF (which does not usually happen until subprocess exit), to get more 'realtime' at least read by lines via readline() in a loop
Any object connected to a file descriptor can be passed to subprocess.Popen including sys.stdout!
com=subprocess.Popen(args,stdout=sys.stdout,stderr=sys.stderr)
Note that this may not work in some python shells.
subprocess.Popen constructor. This has nothing to do with output redirection.
stdout=sys.stdout. By default the standard output is inherited i.e., if you you don't pass stdout parameter then the child process prints to the same place as the parent Python script (unless sys.stdout is replaced incorrectly).