Groups are an essential part of how discretionary access control (DAC) is implemented on Linux and, in general, on any Unix-based operating system. The creation, modification, and removal of groups are relatively straightforward operations which can be carried out using some utilities installed by default.
acl
How to list and manage files attributes on Linux
When using Linux we have many ways to manage access to resources: the most basic one is by setting the appropriate UGO/RWX permissions on files and directories. In some occasions we may also want to make use of the setuid, the setgid and the sticky bit. Furthermore, we can use ACLs (Access Control List) in order to achieve an higher level of granularity or implement Mandatory Access Control security such those based SELinux or AppArmor.
In addition to the strategies mentioned above, on most filesystems we can manipulate a set of “attributes” in order, for example, to make a file immutable.
How to manage WiFi interfaces with rfkill command on Linux
Rfkill is an utility available in the vast majority of Linux distributions, and often installed by default. The utility allows us to list, enable or disable various types of wireless interfaces like WIFI or Bluetooth on Linux.