Question

我需要尝试，除了帮助或任何其他最好的方式来存档我的要求。请帮忙

const char *x ="abc";
const char *y ="defgh";

提供以下输出：

  mount_status = check_output (["mount", "/dev/sr{}".format(x), "/mnt"])

如果我得到选项1，那么它应该继续

如果我获得选项2，那么它应该终止程序。

我尝试的是在下面的脚本中，它无法正常工作

   1. If medium does not found then below messages appears and stops the program.



mount: no medium found on /dev/srX
Traceback (most recent call last):
  File "test.py", line 39, in <module>
    software_foundation()
  File "test.py", line 31, in software_foundation
    mount_status = check_output (["mount", "/dev/sr{}".format(x), "/mnt"])
  File "/usr/lib64/python2.7/subprocess.py", line 573, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['mount', '/dev/srX', '/mnt']' returned non-zero exit status 32






2. If medium exits but it already mounted then below messages appears and stops the program.
mount: /dev/srX is write-protected, mounting read-only
mount: /dev/srX is already mounted or /mnt busy
       /dev/srX is already mounted on /mnt
Traceback (most recent call last):
  File "test1.py", line 39, in <module>
    software_foundation()
  File "test1.py", line 31, in software_foundation
    mount_status = check_output (["mount", "/dev/sr{}".format(x), "/mnt"])
  File "/usr/lib64/python2.7/subprocess.py", line 573, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['mount', '/dev/srX', '/mnt']' returned non-zero exit status 32

Answer 1

我从你的问题中收集到你不知道怎么写try...except。

将try放在引发要捕获的异常的行之前。将except放在if之前 - 测试如何处理异常。

import subprocess 
import sys 

for x in range(0,5):
    try:
        mount_status = subprocess.check_output (["mount", "/dev/sr{}".format(x), "/mnt"])
    except subprocess.CalledProcessError as details:
        if "is write-protected, mounting read-only" in details: 
            break
        elif "is already mounted on /mnt" in details:
            print "/mnt has already mounted. Unmount /mnt and rerun the script"
            sys.exit()

检查mount_status - 测试中的if无效，因为如果您对check_output()的调用成功，则只会获得一个值。如果命令的返回码非零，则check_output()会引发异常，因此mount_status的赋值永远不会发生。

尝试除了python以防程序终止

1 个答案: