Lesson 3 of 6 · About 6 minutes
Users, groups, and administrator access
Learn the concept.
A program runs with an identity and a set of permissions. Having a file’s name does not mean your account can read or change it.
Read the three permission groups
Regular file: -rw-r----- root analysts auth.log.
| Who | Bits | Meaning |
|---|---|---|
| Owner: root | rw- | Read and write |
| Group: analysts | r-- | Read |
| Others | --- | No file access |
Read the visualFor the regular file rw-r----- owned by root:analysts, what does group access permit?
The middle three bits are r--, so the group has read permission. This simplified example assumes directory access and no other restrictions.
Inspect the identity
whoami shows the current account name in our terminal. Groups collect accounts for permission assignment. The lab’s learner account belongs to the analysts group.
Read a simple permission listing
For a regular file, rw-r----- gives the owner read and write, the group read, and others no access. The initial - in ls -l means a regular file; d means a directory. Directory permission meanings differ.
Keep elevation deliberate
Administrative access can affect more of the system. A permission error is a reason to check the approved task and access, not to automatically grant yourself more power. Real systems can also have ACLs and additional controls.
Put it in context
The practice file auth.log belongs to root and the analysts group with mode rw-r-----. Learner can read it through group access but cannot edit it. That is enough to investigate a copy of the log.
Make a decision.
Explore the practice space, then answer the check-in below. A correct answer lets you save this lesson to your progress.
YOUR PRACTICE SPACE
Try the idea for yourself.
Enable JavaScript to explore this fictional exercise. The explanation and visual above remain available.
Take this with you.
Match the account, group, and requested action to the actual permission.
Next lesson: Processes and background services