Where a file's permissions come from
umask: why a file is born 644 or 664 depending on context — and the setting to fix instead of stacking chmods.
20 minutesTechnical content last reviewed on 16 Sept 2026
This lesson is for signed-in learners
Create an account to subscribe and record your learning progress.
What this lesson builds
- Granting exactly the access a person or process needs
- Reading system state without over-reading it