How do I pipe a subprocess call to a text file?
Question:
subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml", "/tmp/video_xml"])
RIght now I have a script that I run. When I run it and it hits this line, it starts printing stuff because run.sh has prints in it.
How do I pipe this to a text file also? (And also print, if possible)
Answers:
The options for popen can be used in call
args,
bufsize=0,
executable=None,
stdin=None,
stdout=None,
stderr=None,
preexec_fn=None,
close_fds=False,
shell=False,
cwd=None,
env=None,
universal_newlines=False,
startupinfo=None,
creationflags=0
So…
myoutput = open('somefile.txt', 'w')
subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml", "/tmp/video_xml"], stdout=myoutput)
Then you can do what you want with myoutput
Also, you can do something closer to a piped output like this.
dmesg | grep hda
would be:
p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]
There’s plenty of lovely, useful info on the python manual page.
If you want to write the output to a file you can use the stdout-argument of subprocess.call.
It takes either
None (the default, stdout is inherited from the parent (your script))subprocess.PIPE (allows you to pipe from one command/process to another)- a file object or a file descriptor (what you want, to have the output written to a file)
You need to open a file with something like open and pass the object or file descriptor integer to call:
f = open("blah.txt", "w")
subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml", "/tmp/video_xml"], stdout=f)
I’m guessing any valid file-like object would work, like a socket (gasp :)), but I’ve never tried.
As marcog mentions in the comments you might want to redirect stderr as well, you can redirect this to the same location as stdout with stderr=subprocess.STDOUT. Any of the above mentioned values works as well, you can redirect to different places.
subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml", "/tmp/video_xml"])
RIght now I have a script that I run. When I run it and it hits this line, it starts printing stuff because run.sh has prints in it.
How do I pipe this to a text file also? (And also print, if possible)
The options for popen can be used in call
args,
bufsize=0,
executable=None,
stdin=None,
stdout=None,
stderr=None,
preexec_fn=None,
close_fds=False,
shell=False,
cwd=None,
env=None,
universal_newlines=False,
startupinfo=None,
creationflags=0
So…
myoutput = open('somefile.txt', 'w')
subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml", "/tmp/video_xml"], stdout=myoutput)
Then you can do what you want with myoutput
Also, you can do something closer to a piped output like this.
dmesg | grep hda
would be:
p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]
There’s plenty of lovely, useful info on the python manual page.
If you want to write the output to a file you can use the stdout-argument of subprocess.call.
It takes either
None(the default, stdout is inherited from the parent (your script))subprocess.PIPE(allows you to pipe from one command/process to another)- a file object or a file descriptor (what you want, to have the output written to a file)
You need to open a file with something like open and pass the object or file descriptor integer to call:
f = open("blah.txt", "w")
subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml", "/tmp/video_xml"], stdout=f)
I’m guessing any valid file-like object would work, like a socket (gasp :)), but I’ve never tried.
As marcog mentions in the comments you might want to redirect stderr as well, you can redirect this to the same location as stdout with stderr=subprocess.STDOUT. Any of the above mentioned values works as well, you can redirect to different places.