如何以逐行格式从Popen获取stdout和stderr？

Question

我正在运行下面的Python脚本。当我打印stdout和stderr时，它们会打印成每个字母（请参见下文）。如何让stdout和stderr以每行原始格式打印？

cmd = r"""python ./script.py"""
print cmd
proc = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=True)
output, error = proc.communicate()
for line in output:
    print "in stdout"
    print line
    if 'Onlycloned' in line:
        print "OnlyclonedRadars line matched"
        #logger.info('OnlyclonedRadars line matched')
        radars = line
        radarlist = radars.split(':')[1].strip()
        #radars = 37142113  
    for line in error:
        print "in stderr"
        print line  

输出：

in stderr
2
in stderr
0
in stderr
:
in stderr
5
in stderr
8
in stderr
:
in stderr
4
in stderr
5
in stderr

in stderr
r