Call the system command in Python and get the return

Purpose: Sometimes you need some system information or execute files that are not Python, and you need to call them through the OS module.

Environment: Windows 7 Python 3.5.3

Scene:

1) I work with Python to build a file that the system can run directly, such as the bat batch, which needs to be executed;

2) I am familiar with batching and want to execute commands in Python and get its return information.

Both cases require the import of the OS module:

First case:

Os.open (file, flags[, mode]);

You can open the file in the system with the following parameters:

• FILE--Files to open

• Flags--This parameter can be the following options, separated by "|":

  • Os. O_rdonly: Open in read-only mode

  • Os. O_wronly: Open in write-only mode

  • Os. O_RDWR: Open in read-write mode

  • Os. O_nonblock: does not block when open

  • Os. O_append: Open in Append mode

  • Os. O_creat: Create and open a new file

  • Os. O_trunc: Open a file and truncate it to a length of 0 (Must have write permission)

  • Os. O_EXCL: If the specified file exists, an error is returned

  • Os. O_shlock: Automatic acquisition of shared locks

  • Os. O_exlock: Automatic acquisition of independent locks

  • Os. O_direct: Eliminate or reduce cache effects

  • Os. O_fsync: Synchronous Write

  • Os. O_nofollow: Do not track soft links

• Mode-similar to chmod (), this parameter is commonly used in Linux, the default 0777
  

return value

Returns the descriptor for the newly opened file.

Here are two examples:

1) Operation text file similar to open ()

With Os.open (' Test.txt ', OS. O_rdwr|os. O_creat) as F:os.write (F, ' This is a test. ')

Well, that's it, using it to feel more trouble than open (link).

2) Execute a batch file that already exists

Os.open (' Test.bat ')

Well, it's a simple sentence.

Second case:

Os.popen (command[, mode[, BufSize])

I want to get the current user name:

echo%username% in Windows can output the current user name

user = Os.popen (' echo%username% '). Read ()

Well, that's it, it feels good to use the combination.

This article is from the "Rickyhul" blog, make sure to keep this source http://rickyh.blog.51cto.com/10934856/1947783

Call the system command in Python and get the return