如何使用子进程写入文件

Question

我正在尝试获取 adb logcat 并保存到文件中。我尝试了 POPEN 并调用如下

    f = open("/Users/log.txt")
    subprocess.call(["adb logcat"], stdout=f)
    f_read = f.read()
    print f_read

但我得到错误

  File "testPython.py", line 198, in getadbLogs
    subprocess.call(["adb logcat"], stdout=f)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 522, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1335, in _execute_child
    raise child_exception
**OSError: [Errno 2] No such file or directory**

我不确定我做错了什么。是否可以使用子进程获取 adb logcat 日志？我检查了文件路径是否正确。

Answer 1

因为您在读取模式下打开了f (r)。如果不选择模式，默认模式为r模式。

要写入文件，您应该使用w 模式，如下所示：

f = open("/Users/log.txt", 'w')
subprocess.call(["adb logcat"], stdout=f)
f.close()

f = open("/Users/log.txt")
f_read = f.read()
print f_read
f.close()

而使用with自动关闭文件会更简单：

with open("/Users/log.txt", 'w') as f:
    subprocess.call(["adb logcat"], stdout=f)

with open("/Users/log.txt") as f:
    f_read = f.read()

print f_read