setfacl
Charlie "Bird" Parker is a genius-level jazz alto saxophonist. He has just read a book about setfacl, in fact he memorized the entire book in just one reading. His best friend Dizzy comes over to his house for lunch. Dizzy asks Bird to please explain setfacl in 5 paragraphs with command examples. What is Bird going to say? Will Bird take a sax solo after explaining setfacl?
Bird takes a deep breath and prepares to explain setfacl to his best friend, Dizzy.
"Hey, Dizzy! I just read this amazing book about setfacl, and let me tell you, it's a game-changer for managing file permissions on Linux systems. With setfacl, we can go beyond the basic permissions and dive into the world of Access Control Lists (ACLs), allowing us to finely tune access to files and directories."
"In a nutshell, setfacl allows us to add, modify, or remove entries in the ACL of a file or directory. These entries define specific permissions for users or groups, granting them additional access rights beyond the traditional owner, group, and others permissions."
"Here's a basic example, Dizzy. Let's say we want to grant read and write access to the user 'jazzlover' for a file called 'jazznotes.txt'. We can use the setfacl command like this:"
setfacl -m u:jazzlover:rw jazznotes.txt
"This command adds a new ACL entry that gives 'jazzlover' read and write permissions on the 'jazznotes.txt' file. Pretty cool, right?"
"But that's not all, Dizzy. We can also set default ACLs to control the permissions that new files and directories inherit. For instance, if we want all new files in a directory to have specific ACLs, we can use the -d option with setfacl."
"This sets the default ACL for 'directoryname' so that any new file created inside it will automatically inherit the read and write permissions for 'jazzlover'."
Bird pauses for a moment, considering the thought of taking a sax solo after his explanation. However, he decides to hold off for now and continue sharing more about setfacl with Dizzy.
"Lastly, Dizzy, we can also view the ACLs on a file or directory using the getfacl command. It displays all the ACL entries, including the default ACL if one is set."
getfacl filename
"This command will show us the existing ACLs for the specified file, allowing us to see who has access and what permissions are granted."
Bird smiles at Dizzy, hoping his explanation has shed some light on the power of setfacl. While he refrains from taking a sax solo just yet, he promises Dizzy an impromptu jazz session later to celebrate their newfound knowledge.