运行下面的 Python 脚本时，它首先保存所有 shell 命令输出，然后将打印消息输出保存在文件中

Question

#!/usr/bin/python
import subprocess
f = open("output.txt", "w")
print>>f, "/etc/hosts output:n"
print>>f, "____________________n"
subprocess.call('cat /etc/hosts',stdout=f,shell=True)
print>>f, "hostname output:n"
print>>f, "____________________"
subprocess.call('hostname',stdout=f,shell=True)

下面是输出.txt文件。

127.0.0.1       localhost.localdomain localhost
::1     localhost6.localdomain6 localhost6
127.0.0.1       localhost localhost.localdomain
::1         localhost localhost.localdomain
node1.example.com
/etc/hosts output:

---

hostname output:

---

我们需要这个输出.txt

格式如下。

/etc/hosts output:
 ____________________
127.0.0.1       localhost.localdomain localhost
::1     localhost6.localdomain6 localhost6
127.0.0.1       localhost localhost.localdomain
::1         localhost localhost.localdomain

hostname output:
____________________
node1.example.com

Answer 1

子进程将与应用程序异步工作，这就是为什么这种行为，但是您也可以这样做：

#!/usr/bin/python
import subprocess
f = open("output.txt", "w")
#print>>f, "/etc/hosts output:n"
#print>>f, "____________________n"
subprocess.call('echo "/etc/hosts output:" n echo "____________________" n cat /etc/hosts',stdout=f,shell=True)
#print>>f, "hostname output:n"
#print>>f, "____________________"
subprocess.call('echo "hostname output:" n  echo "____________________" n hostname',stdout=f,shell=True)