Linux shell: understanding Umask with examples

In this article I’ll show you what’s umask and how to use it to get the right permissions on your files. umask (user mask) is a command and a function in POSIX environments that sets the file mode creation mask of the current process which limits the permission modes for files and directories created by the process. A process may change the file mode creation mask with umask and the new value is inherited by child processes.