LCA Cheat Sheet 2026

The 30 highest-yield LCA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the purpose of the 'tune2fs -c 20 /dev/sdb1' command? → Set maximum mount count before fsck is forced to 20
2. Which command displays all running and stopped Docker containers? → docker ps -a
3. Which configuration directive in /etc/resolv.conf allows the resolver to try multiple domain suffixes when resolving a short hostname? → search
4. What is the '/etc/yum.repos.d/' directory used for? → Storing .repo configuration files that define YUM/DNF package repositories
5. A file has permissions 664. What is the symbolic equivalent for the 'others' portion? → r--
6. What does setting 'cpu_shares' on a cgroup accomplish for a virtual machine? → Sets the relative CPU scheduling weight
7. In PostgreSQL, what does VACUUM do? → Reclaims storage occupied by dead tuples and updates visibility maps
8. What is the purpose of 'nice' and 'renice' commands in Linux performance tuning? → Adjusting a process's scheduling priority to influence CPU time allocation
9. Which command shows which SELinux Boolean values are currently enabled? → getsebool -a
10. What does the 'kubectl get pods -n kube-system' command do? → Lists pods running in the kube-system namespace
11. In the context of LCA certification, what is the most important consideration when implementing backup & disaster recovery? → Ensuring alignment with established standards, stakeholder needs, and best practices
12. Which command displays all currently mounted filesystems along with their mount options? → mount
13. Which Apache module enables URL rewriting using regular expressions? → mod_rewrite
14. Which command in MySQL shows all currently running queries and their status? → SHOW FULL PROCESSLIST
15. What is the role of the Docker daemon (dockerd)? → Manages container lifecycle, images, networks, and volumes on the host
16. Which command checks and repairs a Linux file system? → fsck
17. Which file configures system-wide PAM password quality requirements on RHEL-based systems? → /etc/security/pwquality.conf
18. Which command verifies the integrity of an RPM package against its installed file list? → rpm -V packagename
19. What is the purpose of the 'apt-cache showpkg' command? → Displays package dependency and reverse-dependency information
20. Which namespace type isolates process IDs between containers? → pid namespace
21. In Nginx, which directive configures the path to the error log and its severity level? → error_log /var/log/nginx/error.log warn
22. What does the Linux command 'iptables' manage? → Network traffic filtering
23. In Bacula, which daemon manages job scheduling, client catalog, and coordinates the overall backup/restore process? → Director (bacula-dir)
24. Which command initializes a new Terraform working directory and downloads provider plugins? → terraform init
25. Which file persists custom hostname-to-IP mappings on Linux and is consulted before DNS by default? → /etc/hosts
26. Which command lists all files installed by a specific RPM package named 'httpd'? → rpm -ql httpd
27. What is the purpose of the /etc/skel directory? → Stores skeleton (template) files copied into new users' home directories
28. What does the 'nmap -sS' scan type perform? → TCP SYN (stealth) scan
29. A disaster recovery plan calls for a 'warm standby' site. What best describes this? → A site with hardware and software pre-configured but not actively processing live traffic
30. Which command shows real-time disk I/O statistics per device, including read/write throughput? → iostat -xz 1