popen | 易学教程

jruby IO.popen read hangs in action when requests are made to the local dev server

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问题 I just want to send the output of wkhtmltopdf to the user. It shouldn't be so hard. def it send_pdf "file.pdf" end def send_pdf(file) url= url_for(params) # Example: http://localhost:3000/report/it webkit= Rails.root.join('app', 'bin', 'wkhtmltopdf', 'current') cmd= "#{webkit} -q \"#{url_for(params)}\" -" data= IO.popen(cmd).read ############### HANGS HERE ################### send_data(data, type: "application/pdf", filename: file) end Why does it hang and how to fix it? 回答1: I think the clue

Does Popen().stdout.close() return a value?

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问题 I have in the code I maintain: app7z = dirs['mopy'].join('7z.exe').s # path to 7z.exe command = '"%s" a "%s" -y -r "%s\\*"' % (app7z, dstFile.temp.s, srcDir.s) ins = Popen(command, stdout=PIPE, startupinfo=startupinfo).stdout #--Error checking and progress feedback reCompressing = re.compile('Compressing\s+(.+)') regMatch = reCompressing.match reError = re.compile('Error: (.*)') regErrMatch = reError.match errorLine = [] for line in ins: maCompressing = regMatch(line) if len(errorLine) or

C programming - execute another program with sudo privileges

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问题 i have a C program that opens an mp3 and extract the jpg artwork in the same folder. If i execute this program with no root privileges i get a crash. If i execute it with sudo it works normally. Now, i need another C programs who launch the previous program when it needs a jpg artwork for the selected mp3. I tried to call popen("./firstProgram test.mp3" , "r") function or system("/(absolute path)/firstProgram test.mp3") function by calling them even with sudo in the command or not and either

python popen special characters not parsing file

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问题 I am having issues with non ASCII characters. I am using python 2.7.3 python -V Python 2.7.3 I installed http://pymediainfo.readthedocs.org/en/latest/ via easy_install pymediainfo imported as below from pymediainfo import MediaInfo media_info = MediaInfo.parse(os.path.join(path, to, file)) using this with ascii characters is fine for debugging I printed the 'command' from: /usr/local/lib/python2.7/dist-packages/pymediainfo-1.3.5-py2.7.egg/pymediainfo/__init__.py the class that 'runs' the

How can I run an exe file from Python 3.x Windows Service?

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问题 This is very frustrating. I am trying to launch any EXE from a WINDOWS SERVICE . I'm using Python 3.5 and Win10. I created the service inheriting from win32serviceutil.ServiceFramework as I have seen in many examples on the Internet I've tried it with os.startfile() , subprocess.call() , subprocess.Popen() and os.system() and always with the same result. The application's executable (that I launched from the service) is appearing as a subthread (subprocess) no like main process and you don't

Preserve colored output using php's popen

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问题 When using popen in php, is there a way to preserve the colored output a program might generate? Is there maybe a way I can tell the shell to print all color escape sequences, instead of resolving them? 回答1: That depends on the program you are calling. Usually, if a program supports coloured output, it would ask the OS, "am I running on a terminal?" If yes, then it outputs colour codes. If not, it won't. If you run that program through popen() , then the OS would say "no, you're not running

PyQt5界面上调用subprocess.Popen会闪命令窗口的问题

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最近再做一个界面开发，主要实现的点击一个按钮，会执行adb安装应用程序的功能，在调试阶段一切都正常，但打包成一个exe安装程序，安装之后运行，点击按钮会闪一下adb的命令窗口先列出subprocess.Popen方法介绍，里面有很多关键字参数一、subprocess.Popen subprocess模块定义了一个类： Popen class subprocess.Popen( args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0) 划重点： cmd_test = "adb install xxx.apk" subprocess.Popen(cmd_test, shell=True) 这是因为它相当于 subprocess.Popen(["cmd.exe", "-c", cmd_test]) 在*nix下，当shell=False（默认）时，Popen使用os.execvp()来执行子程序所以如果不设置shell这个参数时

进程间通信-管道

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转自： 0giant 管道允许在进程之间按先进先出的方式传送数据，是进程间通信的一种常见方式。管道是Linux 支持的最初Unix IPC形式之一，具有以下特点： 1) 管道是半双工的，数据只能向一个方向流动；需要双方通信时，需要建立起两个管道； 2) 匿名管道只能用于父子进程或者兄弟进程之间（具有亲缘关系的进程）； 3) 单独构成一种独立的文件系统：管道对于管道两端的进程而言，就是一个文件，但它不是普通的文件，它不属于某种文件系统，而是自立门户，单独构成一种文件系统，并且只存在与内存中。管道分为pipe（无名管道）和fifo（命名管道）两种，除了建立、打开、删除的方式不同外，这两种管道几乎是一样的。他们都是通过内核缓冲区实现数据传输。 pipe用于相关进程之间的通信，例如父进程和子进程，它通过pipe()系统调用来创建并打开，当最后一个使用它的进程关闭对他的引用时，pipe将自动撤销。 FIFO即命名管道，在磁盘上有对应的节点，但没有数据块 ——换言之，只是拥有一个名字和相应的访问权限，通过mknode()系统调用或者mkfifo()函数来建立的。一旦建立，任何进程都可以通过文件名将其打开和进行读写，而不局限于父子进程，当然前提是进程对FIFO有适当的访问权。当不再被进程使用时，FIFO在内存中释放，但磁盘节点仍然存在。管道的实质是一个内核缓冲区

Stay in directory with popen

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问题 I want to make some C++ program and I'm using function popen here to send commands to command line in Unix. It works fine, but when I call cd directory , the directory doesn't change. I thing that it's same when I try to run cd directory in some script, after finishing script directory path change back. So, scripts I must run like . ./script.sh not ./sript.sh , but how to do that with popen function? I have tried to add ". " before first argument of popen , but running ". ls" makes error.

subprocess.Popen() doesn't redirect output to file

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问题 Check.cpp int main(int argc, char** argv) { string file = ""; ifstream inFile; int x; file = argv[1]; inFile.open(file.c_str()); while (inFile >> x) cout << x << endl; return 0; } Print.py from __future__ import with_statement from shutil import copy import subprocess import filecmp import sys count = 0 f = open ("filename.txt","r") file1 = open ("file1.txt","w") file2 = open ("file2.txt","w") file3 = open("out1.txt","w") file4 = open("out2.txt","w") for line in range(1,2): firstline = f