popen

Remove
from python string

由 ￡可爱￡侵袭症＋ 提交于 2019-12-22 10:28:59
问题 When you run something through popen in Python, the results come in from the buffer with the CR-LF decimal value of a carriage return (13) at the end of each line. How do you remove this from a Python string? 回答1: You can simply do s = s.replace('\r\n', '\n') to replace all occurrences of CRNL with just NL, which seems to be what you want. 回答2: buffer = "<text from your subprocess here>\r\n" no_cr = buffer.replace("\r\n", "\n") 回答3: If they are at the end of the string(s), I would suggest to

Print out the output of os.popen() without buffering in python

由 ℡╲_俬逩灬. 提交于 2019-12-22 09:56:29
问题 Let's say that I have a process that prints out some data something like this ruby code. 1.upto(10) { |i| puts i puts "\n" sleep 0.6 } I want to have a python code that spawns this process, and read data from it to print it out. import os import sys cmd = "ruby /Users/smcho/Desktop/testit.rb"; pingaling = os.popen(cmd,"r") while 1: line = pingaling.readline() if not line: break print line, sys.stdout.flush() pingaling.close() The problem of this code is that it doesn't print the number one by

Keeping a pipe to a process open

由 走远了吗. 提交于 2019-12-22 08:49:35
问题 I have an app that reads in stuff from stdin and returns, after a newline, results to stdout A simple (stupid) example: $ app Expand[(x+1)^2]<CR> x^2 + 2*x + 1 100 - 4<CR> 96 Opening and closing the app requires a lot of initialization and clean-up (its an interface to a Computer Algebra System), so I want to keep this to a minimum. I want to open a pipe in Python to this process, write strings to its stdin and read out the results from stdout . Popen.communicate() doesn't work for this, as

popen vs system: is popen as evil as system?

由 夙愿已清 提交于 2019-12-22 05:21:58
问题 popen buffers output while system does not. is that the only difference? I understand that popen and system both run the command through the shell. However, is popen() as evil as system()? 回答1: Look, the whole thing about "system being evil" is, at heart, people who don't think about the security consequences of their particular use case. The only reason system is "more evil" than doing your own fork/dup/exec is that used badly, it's possible for someone to introduce a malicious command line.

what is the difference between popen() and system() in C

由 余生颓废 提交于 2019-12-21 06:56:11
问题 I want to execute a binary within my C code. Which is better to execute with? popen() or system() EDIT : I tried to use system , but the process executing seems to get stuck in the end and does not return to my code. Any suggestions on what to do? Thanks 回答1: popen() gives you control over the process's input or output file streams. system() doesn't. If you don't need to access the process's I/O, you can use system() for simplicity. system() is in C89 and C99; popen() is Posix only (though

Python os.popen() 方法

由 霸气de小男生 提交于 2019-12-21 06:26:36
简述 就是新建一个 管道 执行一个命令。 方法是os.popen(命令,权限,缓冲大小) 比如 a = 'mkdir def' b = os.popen(a,'r',1) print b 就是等同于使用命令去创建了一个def的文件夹,r是其权限,1是缓冲大小。第二个第三个参数都是可选的。 详细分析： os.popen() 方法用于从一个命令打开一个 管道 。 语法 popen() 方法语法格式如下： os.popen(command[, mode[, bufsize]]) 参数 command -- 使用的命令。 mode -- 模式权限可以是 'r'(默认) 或 'w'。 bufsize -- 指明了文件需要的缓冲大小：0意味着无缓冲；1意味着行缓冲；其它正值表示使用参数大小的缓冲（大概值，以字节为单位）。负的bufsize意味着使用系统的默认值，一般来说，对于tty设备，它是行缓冲；对于其它文件，它是全缓冲。如果没有改参数，使用系统的默认值。 实例 以下实例演示了 popen() 方法的使用： #!/usr/bin/python # -*- coding: UTF-8 -*- import os, sys # 使用 mkdir 命令 a = 'mkdir nwdir' b = os.popen(a,'r',1) print b 其实就是开了个管道去执行另外的命令 来源：

Can Python open a mp3 file [closed]

由 冷暖自知 提交于 2019-12-21 04:22:13
问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 12 months ago . Is it possible to open an mp3 file in Python (possible using Popen ) and I don't mean to run it in the program I mean as a separate window in media player or whatever just for it to open it when I call the function and if so how? 回答1: Opening a file with its associated

Python: Using popen poll on background process

由 青春壹個敷衍的年華 提交于 2019-12-20 09:55:42
问题 I am running a long process (actually another python script) in the background. I need to know when it has finished. I have found that Popen.poll() always returns 0 for a background process. Is there another way to do this? p = subprocess.Popen("sleep 30 &", shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE) a = p.poll() print(a) Above code never prints None . 回答1: You don't need to use the shell backgrounding & syntax, as subprocess will run the process in the background by itself

Handling tcpdump output in python

由 折月煮酒 提交于 2019-12-20 09:47:11
问题 Im trying to handle tcpdump output in python. What I need is to run tcpdump (which captures the packets and gives me information) and read the output and process it. The problem is that tcpdump keeps running forever and I need to read the packet info as soon as it outputs and continue doing it. I tried looking into subprocess of python and tried calling tcpdump using popen and piping the stdout but it doesnt seem to work. Any directions on how to proceed with this. import subprocess def

Python执行脚本方法

由 ⅰ亾dé卋堺 提交于 2019-12-18 22:35:17
Python中调用shell脚本，常用的函数有os.system、os.popen()和subprocess.Popen() os.system方法 语法：os.system(cmd) os.system()执行过程中主要执行了：fork()出一子进程；子进程调用exec()执行命令。 例1： >>> import os >>> os.system('dir D:\Python') 执行成功，返回0。 例2： import os res = os.system('ping www.baidu.com -n 3') if res == 0: print('成功') else: print('失败了') 执行结果： 注： 1).os.system()执行cmd指令，返回结果0表示执行成功，返回1表示失败。 2).os.system()无法获取在cmd输出的内容。 3).os.system()调用外部系统命令，返回命令结果码，无法获取命令执行输出结果。 os.popen方法 语法：popen(cmd, mode='r', buffering = -1) 参数： cmd：要执行的命令。 mode：打开文件的模式，默认为'r'，用法与open()相同。 buffering：(可选参数)，0表无缓冲；1表行缓冲；-1表默认缓冲值； os.popen()方法会打开一管道
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