90 days of DevOps by Mahesh Joshi
Mastering Linux File Permissions and ACLs:

Mastering Linux File Permissions and ACLs:

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Mahesh Joshi
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3 min read

Hey there, fellow DevOps enthusiasts! Welcome back to Day 6 of my 90-day DevOps challenge. Today, we’re diving into the nitty-gritty of file permissions and access control lists (ACL) in the Linux universe. Buckle up, it’s about to get interesting!

Linux File Permissions and Ownership Demystified

In the vast realm of Linux, file permissions and ownership are like the gatekeepers to your digital kingdom. Picture this: when a file is born, it gets tagged with a set of permissions dictating who gets to read, write, or do a little victory dance with it. Plus, there’s an owner (the file’s creator) and a group (a squad of users with similar privileges).

Permission Party

Let’s break it down for our three main VIPs:

  1. Owner: The big cheese who birthed the file.

This person can tweak permissions and do whatever they please with the file. It’s like having the master key to the kingdom, and they can even switch up the ownership using the chown command.

# Change owner of a file
chown new_owner:new_group file.txt

2. Group: The cool clique that co-owns the file.

  • Group permissions decide what the gang can do with the file. And yes, you can reshuffle the group using the chgrp command if needed
# Change group of a file
chgrp new_group file.txt

3. Others: Everyone else in the digital realm.

  • Other users’ permissions are fair game for tweaking using the chmod command. It's like playing the puppet master for users not in the owner or group squad
# Change permissions of a file for others
chmod o+rwx file.txt

Let’s Get Hands-On!

Time for a little practical magic! Create a simple file, peek at its initial permissions with ls -l, and then go wild with the chmod command. Watch the permission dance with each tweak. Trust me, this hands-on playtime will make Linux file permissions your new best friend.

Deep Dive into File Permissions

Building on our hands-on adventure, let’s deep-dive into an article about file permissions. We’re talking:

  • A behind-the-scenes tour of Linux file permissions and why they’re the superheroes of system security.

  • Meeting the permission cast: owner, group, and others, and understanding their roles in this access control drama.

  • Roll up your sleeves for practical examples using chmod, chown, and chgrp commands. Real-world scenarios included!

# Example of changing permissions
chmod u+x,g-w,o+r file.txt
  • Top-notch tips for managing file permissions in a production setting. Cue the concept of least privilege — it’s the VIP pass for secure environments.

Keep an eye out for the upcoming article on my blog. We’re unlocking the secrets of file permissions in Linux, complete with real-world stories and pro tips.

Access Control Lists (ACL) — A Little Extra Spice

But wait, there’s more! Linux comes with a bonus feature — Access Control Lists (ACL). These bad boys offer even more control over file access, beyond the classic owner, group, and others trio.

ACL Unveiled

As part of today’s mission, let’s dig into ACL. Read up on what it brings to the table and then give the getfacl and setfacl commands a spin. They let you peek at and tweak ACL for files and directories, taking your access control game to a whole new level.

# Get ACL for a file
getfacl file.txt

# Set ACL for a file
setfacl -m u:new_user:rw- file.txt

I hope today’s journey into file permissions and ACL adds some spice to your DevOps adventure. Keep that curiosity alive and keep exploring the magical world of Linux and DevOps.

Happy learning and tinkering! 🚀

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