Python/External commands

執行外部命令的傳統方式是執行os.system():

import os
os.system("dir")
os.system("echo Hello")
exitCode = os.system("echotypo")

從Python 2.4開始可以使用subprocess模塊:

subprocess.call(["echo", "Hello"])
exitCode = subprocess.call(["dir", "nonexistent"])

執行外部命令並讀取其輸出的傳統方式是通過 popen2 模塊：

import popen2
readStream, writeStream, errorStream = popen2.popen3("dir")
# allLines = readStream.readlines()
for line in readStream:
  print(line.rstrip())
readStream.close()
writeStream.close()
errorStream.close()

從Python 2.4開始可以使用subprocess模塊:

import subprocess
process = subprocess.Popen(["echo","Hello"], stdout=subprocess.PIPE)
for line in process.stdout:
   print(line.rstrip())

Keywords: system commands, shell commands, processes, backtick, pipe.

外部連結

• 17.1. subprocess — Subprocess management, python.org, since Python 2.4
• 15.1. os — Miscellaneous operating system interfaces, python.org
• 17.5. popen2 — Subprocesses with accessible I/O streams, python.org, deprecated since Python 2.6