Not able to read subprocess output

Question

I am executing the python command,

proc = subprocess.Popen(cmd, shell=False, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, )

after executing command i want to read the stderr and stdout

res = proc.stderr.read()

in res i am expecting any error or ' '

but the reading the stderr is taking infinite time is get hang not reading the values what ever the result it.it goes in infinite time.

Some time back same code is working fine but not idea why its not reading stderr now.

Any Hint, thanks.

Senthil Kumaran · Accepted Answer · 2012-02-06 13:59:34Z

1

Instead of explicitly calling stderr.read(), just do a communicate on the proc.

output, error = proc.communicate()

That way you would get the output and error by communicating with the process.

answered Feb 6, 2012 at 13:59

Senthil Kumaran

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3 Comments

Shashi Over a year ago

I tried with the same but the reading the proc taking infinite time ,:( dont know why...!!

Senthil Kumaran Over a year ago

Shashi, then your process is blocking, the problem is with your cmd which you are passing. It is perhaps waiting for some input. Try a different command, or as you sending stdin to PIPE as well, do proc.communicate('input\n')

Shashi Over a year ago

@ Senthil Kumaran ok sure i will try that.

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