os.umask() in Python is used to set the current numeric value umask and get the previous value umask .
umask denotes the user file creation mode mask . This is used to determine the permissions on newly created files or directories.
Syntax: os.umask (mask)
mask : An integer value denoting a valid umask value.
Return Type: This method sets the current umask value and returns an integer value which represents the previous umask value.
Code # 1 : Using the os.umask () method
Current umask: 18 Previous umask: 54
Code # 2: Transfer octal value to as a parameter in the os.umask () method
Current umask: 511 Previous umask: 18
Looks like this is new as of Python 3.4 -
from pathlib import Path Path("path/to/file.txt").touch()
This will create a
file.txt at the path.
Create a file at this given path. If mode is given, it is combined with the process‚Äô umask value to determine the file mode and access flags. If the file already exists, the function succeeds if exist_ok is true (and its modification time is updated to the current time), otherwise FileExistsError is raised.
There are many fiddly things to take care of when becoming a well-behaved daemon process:
prevent core dumps (many daemons run as root, and core dumps can contain sensitive information)
behave correctly inside a
set UID, GID, working directory, umask, and other process parameters appropriately for the use case
close all open file descriptors, with exclusions depending on the use case
behave correctly if started inside an already-detached context, such as
set up signal handlers for sensible daemon behaviour, but also with specific handlers determined by the use case
redirect the standard streams
stderr since a daemon process no longer has a controlling terminal
handle a PID file as a cooperative advisory lock, which is a whole can of worms in itself with many contradictory but valid ways to behave
allow proper cleanup when the process is terminated
actually become a daemon process without leading to zombies
Some of these are standard, as described in canonical Unix literature (Advanced Programming in the UNIX Environment, by the late W. Richard Stevens, Addison-Wesley, 1992). Others, such as stream redirection and PID file handling, are conventional behaviour most daemon users would expect but that are less standardised.