Hands-on Lab·Red Hat Certified System Administrator
Special Permissions: SUID, SGID and Sticky Bit
Not a separate objective, and assumed by two that are: the collaborative directory in the groups objective needs SGID, and diagnosing permissions needs you to read an `s` or a `t` where you expected an `x`. All three bits are set here and their effects measured with real users.
File Systems Guide 42 of 67 Intermediate
- OSRHEL 10.0 (Coughlan)
- Kernel6.12.0-55.9.1.el10_0
- dnf4.20.0
- Flatpak1.16.0
- TimeAbout 12 min
- Reviewed23 August 2026
Written against the versions above. The three bits share a fourth octal digit: **4** SUID, **2** SGID, **1** sticky. `chmod 2770` is SGID plus `rwxrwx---`. In symbolic form they are `u+s`, `g+s` and `+t`.
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| RHCSA-A01 | 192.168.0.31 | RHEL 10.0 (Coughlan) | Practice node (graded) - spare /dev/sda | 2 Core | 4 GB | 50 GB + 15 GB |
Before you start
- A sudo-capable account.
- The session reuses the users and directory from
guide 41and removes them.
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SUID, and the two you already rely on
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SGID on a directory
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The sticky bit, and why `/tmp` works