# Linux troubleshooting and learner FAQ

## Diagnostic sequence

1. Reproduce the failure in a disposable workspace and record the exact command and exit status.
2. Check the current directory, input paths and resolved symlinks with `pwd`, `stat` and `realpath`.
3. Check command lookup with `type` and `command -v`; inspect relevant exported variables with `env` without recording secrets.
4. Inspect owner, group, mode and parent-directory traversal before changing permissions.
5. For a missing library, inspect `ldd` output and package provenance. Do not apply a global `LD_LIBRARY_PATH` workaround.
6. For capacity errors, compare `df`, `du` and quota where enabled. For a busy process or port, inspect `ps`, `pgrep` and `ss` before acting.
7. Change only files and processes you own; rerun the exact command and retain before/after evidence.

## Common questions

**Do I need root?** No. The practice work is designed for an ordinary user account. Do not use `sudo` to conceal a path, package, or permission problem.

**Are practice results saved?** Knowledge-check results are shown immediately. Anonymous lesson markers remain only in the current browser.

**What if an EDA tool is not installed?** Record the command lookup and its exit status. Use only the environment supplied or approved for the lab.

**Can I share assignment solutions?** Do not publish complete solutions or another participant's work. Share conceptual questions and reproducible symptoms through the approved support route.

**Which Linux release is supported?** The reference is CentOS Stream 10. Other releases may work for introductory commands, but tool compatibility and assignment reproducibility are validated only on the approved reference environment.