python popen不打印标准输出

Question

i am trying to run a command racadam from dell(its a command line tool), into a subprocess.popen.

but I cant get back the stdout, or the stderr. this is what I am doing.

prog = "C:\Program Files\Dell\SysMgt\\rac5\\racadm.exe"
pp = subprocess.Popen(prog, shell=True,stdout=subprocess.PIPE,stderr=subprocess.PIPE)
pp.communicate()
print pp.communicate()

print pp.communicate()[0]
print pp.communicate()[1]

print pp.stdout.readlines()
print pp.stderr.readlines()

out, err = pp.communicate()
print out
print err

and I just get

('', '')


[]
[]

when it should be printing the help with what arguments do what.

the funny thing is I can see that program terminal opening, printing some lines and then close super super fast. so I know that the program is running I just cant get the information back to python =( may I bee missing some steps? or is there a hidden trick?

thanks guys.

Answer 1

Not sure if you have actually written tdout instead of stdout while running your code

Try this

pp = subprocess.Popen(prog, shell=True,stdout=subprocess.PIPE,stderr=subprocess.PIPE)
out, err = pp.communicate()
if pp.returncode == 0:
   final = out
else:
   final = err

print "Final output/Error is "+final