如何在Python中处理管道和输出?
我正试图在python脚本中执行此命令:如何在Python中处理管道和输出?,python,subprocess,avprobe,Python,Subprocess,Avprobe,我正试图在python脚本中执行此命令: avprobeCommand = "avprobe -of json -show_streams {0} | grep '\"duration\"' | sed -n 1p | sed 's/ //g'".format(hiOutput) output = subprocess.check_output([avprobeCommand]) 我不断得到: Traceback (most recent call last): File "/Sy
avprobeCommand = "avprobe -of json -show_streams {0} | grep '\"duration\"' | sed -n 1p | sed 's/ //g'".format(hiOutput)
output = subprocess.check_output([avprobeCommand])
我不断得到:
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 552, in __bootstrap_inner
self.run()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 505, in run
self.__target(*self.__args, **self.__kwargs)
File "/Users/jmakaila/Documents/Development/Present/Web/video_dev/present-live-transcoder/Transcoder.py", line 60, in transcode
output = subprocess.check_output([avprobeCommand])
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 537, in check_output
process = Popen(stdout=PIPE, *popenargs, **kwargs)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 679, in __init__
errread, errwrite)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1228, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
我已经尝试过将参数拆分,但是我一直得到-of json-show_streams部分的一个错误,记录如下:
subprocess.check_output(["avprobe", "-of json", "-show_streams", "{0}".format(hiOutput)
将命令作为字符串传递,并传递
shell=True
:
import pipes
import subprocess
avprobeCommand = """avprobe -of json -show_streams {0} | grep '"duration"' | sed -n 1p | sed 's/ //g'""".format(pipes.quote(hiOutput))
output = subprocess.check_output(avprobeCommand, shell=True)
更新:应使用转义参数。(如果使用Python 3.3+,请使用。在您的情况下,可以将后处理移到Python中:
import json
from subprocess import check_output as qx
data = json.loads(qx(["avprobe", "-of", "json", "-show_streams", hiOutput]))
result = data["duration"] # grep '"duration"'
.partition("\n")[0] # sed -n 1p
.replace(" ", "") # sed 's/ //g'
有关更一般的情况,请参见@J.F.Sebastian,谢谢您的评论。我根据您的评论更新了答案。这里列出了替代方法:我建议使用
管道
模块: