os.system

问题 Honestly, I just don't understand the lingo of "non-zero" status to really interpret what's going on or what that means (it wasn't even defined) on help pages. What are some examples of using python to call other scripts in which these processes of subprocess.call subprocess.check_output subprocess.popen really differ from each other? When would you use either of those, and what are the disambiguated details of these methods? Should I be using os.system instead if I wanted simple OS calls?

问题 I have code which runs a webcamera on a linux pc using the gst-launch command. When I kill the process, the webcamera window does not turn off, but the program stops running. I want the webcamera window also to be closed. Can you help me on this? import subprocess import time import os import signal cmd = "gst-launch-1.0 -v v4l2src ! video/x-raw,format=YUY2 ! videoconvert ! autovideosink" process = subprocess.Popen(cmd, shell = True) time.sleep(5) #print(subprocess.Popen.pid) #process

问题 On my machine, I have some software which takes commands in the terminal and returns a list of values. To run it, I have to type something like: pdv -t filename I am trying to run it as part of a python programme. When I run the following: os.system('pdv -t %s' % (epoch_name)) then I get the values that I desire returned to my terminal (where epoch_name is the variable name for the filename). But when I try to write the result to a file: os.system('pdv -t %s % "(epoch_name)" > 123.txt') the

问题 I wanted to turn on and turn off crone job from os.system command written in python. Basically, using sed command to comment/uncomment the crontab line to control the job schedule. But when I put this command as shown below, python interpret as text after # as comment. import os os.system("crontab -l | sed '/^\*.*heightSQL.py/s/^/#/' | crontab -") Is there any way to tell python not to interpret # as comment symbol? 回答1: You have no issue with the hash symbol but your quoting is not proper.

问题 Greetings learned fellows. Running 32bit Python2.7 on Windows 7. I'm have a question regarding including GDAL executables in a pyinstaller build. I am making a system call to run two GDAL functions from the FWTools release. These functions are in the PATH variable on windows C:\Program Files (x86)\FWTools2.4.7\bin and so it runs fine from the Python27 environment. However, this path is not carried over to the pyinstaller build. The code in question is calling a GDAL function to re-translate

问题 Greetings learned fellows. Running 32bit Python2.7 on Windows 7. I'm have a question regarding including GDAL executables in a pyinstaller build. I am making a system call to run two GDAL functions from the FWTools release. These functions are in the PATH variable on windows C:\Program Files (x86)\FWTools2.4.7\bin and so it runs fine from the Python27 environment. However, this path is not carried over to the pyinstaller build. The code in question is calling a GDAL function to re-translate

问题 I have a python script which launches several processes. Each process basically just calls a shell script: from multiprocessing import Process import os import logging def thread_method(n = 4): global logger command = "~/Scripts/run.sh " + str(n) + " >> /var/log/mylog.log" if (debug): logger.debug(command) os.system(command) I launch several of these threads, which are meant to run in the background. I want to have a timeout on these threads, such that if it exceeds the timeout, they are

问题 I use an external command inside a python script using firstly: subprocess.Popen(cmd, stdout=subprocess.PIPE) then i get the stdout. The problem is that the result of this external command when executing it inside the script is not the same if i execute it directly in the command line. I use then os.system(cmd) , but the same problem. Is this instructions in python use some buffers? How can i explain the difference between the two results (command line and inside the script). I'm using this

问题 I use an external command inside a python script using firstly: subprocess.Popen(cmd, stdout=subprocess.PIPE) then i get the stdout. The problem is that the result of this external command when executing it inside the script is not the same if i execute it directly in the command line. I use then os.system(cmd) , but the same problem. Is this instructions in python use some buffers? How can i explain the difference between the two results (command line and inside the script). I'm using this

问题 I am writing a python script on a remote server with an old version of python 2.4. In the script I want to issue commands like curl -XPUT 'http://somerul/_search' -d file.txt or an ls -ltrh and capture the outputs of these commands into a variable. For the curl command the output will be a json format that I will parse (please advise if an old json parser is available for me to use).. How can I make these kinds of system calls in the python script and capture the output into a variable? Thank