M15 - Permissions: NTFS and Linux rwx
Permissions: NTFS and Linux rwx
Understand the basic permission models in Linux and Windows, and make small, safe permission changes without treating access control like magic.
- Read the basic Linux rwx permission view.
- Understand that Windows NTFS permissions use a richer ACL model.
- Make one small permission change safely in a practice area.
Why This Matters
Identity answers who is asking. Permissions answer what that identity may do.
This lesson stays focused on the beginner-friendly core:
- Linux often shows permissions as read, write, and execute bits
- Windows NTFS uses access control entries that can be more detailed
- permission changes are safest in a practice directory first
1. Linux: The Quick rwx View
On Linux, ls -l gives you a compact permission summary.
ls -l script.sh
A line like -rwxr-xr-- is a compact summary of:
- owner permissions
- group permissions
- other permissions
The important beginner meanings are:
rreadwwritexexecute or traverse
For directories, execute means you can enter or traverse the directory, which is different from executing a program file.
2. Windows: NTFS Permissions Are More Detailed
Windows usually surfaces permissions through NTFS access control entries rather than a short rwx string.
icacls .\example.txt
You will see identities and granted rights rather than one compact permission string.
Skip this pane on Linux.
That does not mean Windows permissions are impossible. It means the representation is richer and less compact.
3. Make Small Changes Safely
If you want to learn permissions properly, do it in a disposable folder with disposable files.
On Windows, start by inspecting with icacls and using the Security tab in a practice folder before making wider changes.
mkdir -p ~/perm-sandbox cd ~/perm-sandbox touch script.sh chmod u+x script.sh ls -l script.sh
Do Not Learn on Production Data
Permission mistakes can lock you out or expose files too broadly. Practice where the cost of a wrong command is low.
What to Ignore for Now
- advanced ACL inheritance details
- special Linux bits such as setuid, setgid, and sticky bit
- large-scale permission remediation
Those topics matter, but they belong after the basic model is stable in your head.
Before You Move On
You are ready when you can:
- explain rwx in plain language
- describe why Windows permissions look different from Linux permissions
- make one permission change in a practice folder and verify the result
Next, we look at temporary privilege elevation and why responsible admins do not stay elevated by default.