如何从 python 运行 cmd.exe 命令？

Question

I would like to run to run a script that opens GUI in which i press a start button which runs (opens, writes, runs) cmd.exe command line.

from tkinter import* 
import sys, string, os
import subprocess
class App:
  def __init__(self, master):
    frame = Frame(master)
    frame.pack()

    self.slogan = Button(frame,text="Start",command=self.start)
    self.slogan.pack(side=LEFT)


  def start(self):
    subprocces.call([])

root = Tk()
app = App(root)
root.mainloop()

Command is following : "ConverterApp.exe" file1.x file1.y

ConverterApp is placed in a random desktop folder. What is does it converts one type of photo to another. And right now i have to use the command above for every photo, so i want to write pyhton program which will convert all .x files in folder to .y.

From my reaserch on the topic i have to use subprocess , bit im kind of lost on how to use it.

Answer 1

Have you looked into using os.system to execute commands? It is simple to use and may be sufficient to accomplish what you are trying to do. On Windows, it usually runs cmd.exe for you.

os.system ( command )

Execute the command (a string) in a subshell. This is implemented by calling the Standard C function system(), and has the same limitations. Changes to sys.stdin, etc. are not reflected in the environment of the executed command. If command generates any output, it will be sent to the interpreter standard output stream.

On Unix, the return value is the exit status of the process encoded in the format specified for wait(). Note that POSIX does not specify the meaning of the return value of the C system() function, so the return value of the Python function is system-dependent.

On Windows, the return value is that returned by the system shell after running command. The shell is given by the Windows environment variable COMSPEC: it is usually cmd.exe, which returns the exit status of the command run; on systems using a non-native shell, consult your shell documentation.

The subprocess module provides more powerful facilities for spawning new processes and retrieving their results; using that module is preferable to using this function. See the Replacing Older Functions with the subprocess Module section in the subprocess documentation for some helpful recipes.

Availability: Unix, Windows.

Answer 2

use the subprocess module.

---

Python 2: https://docs.python.org/2/library/subprocess.html

example:

import subprocess
subprocess.call('ConverterApp.exe', 'file1.x', 'file1.y'])

---

Python 3: https://docs.python.org/3/library/subprocess.html

you can still use subprocess.call , but for Python versions >3.4, it's preferred to use the newer subprocess.run .

example:

import subprocess
subprocess.run(['ConverterApp.exe', 'file1.x', 'file1.y'])

---

Note: in both subprocess.call , and subprocess.run , your command should be passed as a sequence (ie a list).

Answer 3

Following is the snippet which I keep it handy always to run windows commands.

import subprocess
result = []
win_cmd = 'ipconfig'
process = subprocess.Popen(win_cmd,
shell=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE )
for line in process.stdout:
    print line
result.append(line)
errcode = process.returncode
for line in result:
    print line