CELE study plan
CELE · Give each week a clear focus.
8 weeks · About 6 hours per week
Essential Linux concepts and architecture & Filesystem navigation and file management
Diagram the Linux boot sequence from firmware to systemd target and label where the kernel, initramfs, and init system take over
Explain the purpose of /etc, /var, /usr, /home, /tmp, /proc, and /sys and give one real file you would expect to find in each
Navigate the filesystem using cd, pwd, ls with common flags, and absolute versus relative paths without referring to notes
Create, copy, move, rename, and delete files and directories with touch, cp, mv, rm, mkdir, and rmdir, including recursive operations
Use man, --help, and apropos to find the correct option for a command you have not used before
Your checkpoint
A one-page filesystem map with annotated directory purposes plus a shell history log showing 20 navigation and file-management commands you ran successfully
Filesystem navigation and file management & Users, groups, and permissions
Search file contents and filenames using grep, find, and locate with at least three different filter expressions
Set and interpret the nine permission bits and special bits (setuid, setgid, sticky) on files and directories
Convert between symbolic and octal permission notation and apply changes with chmod and chown
Create users and groups with useradd, groupadd, usermod, and passwd, then verify entries in /etc/passwd, /etc/group, and /etc/shadow
Control default file permissions using umask and predict the resulting mode for a new file and directory
Your checkpoint
A lab report showing a shared group directory configured with setgid and a restrictive umask, with ls -l output proving correct ownership and permissions for two test users
Essential Linux concepts and architecture & Processes, jobs, and system services
Inspect running processes with ps, top, and pgrep and identify parent-child relationships and process states
Send signals with kill and pkill to terminate, reload, and pause processes, and explain the difference between SIGTERM and SIGKILL
Manage foreground and background jobs with &, jobs, fg, bg, and nohup
Inspect and control systemd services with systemctl status, start, stop, enable, and disable, and read logs with journalctl
Explain what a systemd unit file contains and locate the unit files for a running service
Your checkpoint
A troubleshooting log in which you start a long-running process, move it between foreground and background, terminate it with the correct signal, and demonstrate enabling and disabling a systemd service with journal evidence
Installing and configuring Linux & Package management and software installation
Walk through the stages of a Linux installation: partitioning, filesystem creation, bootloader placement, and first-boot configuration
Compare ext4, XFS, and swap in terms of use case and create and mount a filesystem on a spare partition or loop device
Edit /etc/fstab to mount a filesystem persistently and verify it with mount -a and findmnt
Use the package manager for your distribution (apt or dnf) to update the package index, install, remove, and query packages
Explain the difference between a package manager and a repository and identify where repository configuration is stored
Your checkpoint
A written install-and-mount runbook that another beginner could follow, plus terminal output showing a newly created filesystem mounted persistently through /etc/fstab and a package installed and removed with the package manager
Networking fundamentals and remote access & Security basics and system administration tasks
Read and interpret IP address, subnet mask, default gateway, and DNS settings using ip addr, ip route, and /etc/resolv.conf
Test connectivity and name resolution with ping, ss, dig, and traceroute and distinguish a routing failure from a DNS failure
Configure and use SSH key-based authentication to log in to a remote host without a password
Transfer files securely with scp or sftp and explain when each is appropriate
Apply basic host hardening steps: disable direct root SSH login, keep the system updated, and review authentication logs
Your checkpoint
A remote-access checklist with screenshots or pasted output proving key-based SSH login works, root login is disabled in sshd_config, and you diagnosed one simulated DNS or routing problem
Shell scripting and command-line utilities & Processes, jobs, and system services
Write a shell script that accepts arguments, uses variables, and exits with meaningful status codes
Use conditionals and loops (if, case, for, while) to process a list of files or command output
Redirect standard input, output, and error and build pipelines with grep, sort, uniq, cut, and wc
Schedule a script with cron and verify execution through logs or output files
Explain the difference between a login shell and a non-login shell and where environment variables such as PATH are set
Your checkpoint
A working backup or log-cleanup script stored in a version-controlled file, scheduled with cron, with a README explaining its arguments, exit codes, and how you verified it ran
Security basics and system administration tasks & Users, groups, and permissions
Explain the principle of least privilege and apply it by creating a limited sudo user instead of working as root
Configure and test sudoers rules safely with visudo and explain the purpose of each field in a rule
Identify common account-security issues such as empty passwords, stale accounts, and world-writable files using command-line checks
Describe how file ownership, permissions, and umask interact to protect sensitive files such as /etc/shadow
Outline a basic patch-management routine including update checks, testing, and rollback considerations
Your checkpoint
A security audit worksheet listing at least five findings from your own system (for example world-writable files or accounts without passwords) with the command used to find each and the remediation you applied or recommend
Essential Linux concepts and architecture & Installing and configuring Linux & Filesystem navigation and file management & Users, groups, and permissions & Processes, jobs, and system services & Networking fundamentals and remote access & Package management and software installation & Shell scripting and command-line utilities & Security basics and system administration tasks
Complete a timed 60-question practice set spanning all nine domains and record your score per domain
Re-study your two lowest-scoring domains using the specific objectives you missed rather than rereading everything
Reperform one hands-on task from each of weeks 1 through 7 without consulting your earlier notes
Explain aloud, in two minutes each, the boot process, permission model, process lifecycle, and package installation flow
Build a one-page command cheat sheet limited to commands you can use from memory
Your checkpoint
A final readiness report showing per-domain practice scores before and after targeted review, plus the cheat sheet and a list of any remaining weak objectives with a plan to close them
Milestones
Week 2: Without notes, create a user, add them to a group, set a shared directory with setgid, and prove with ls -l that another user in the group can create files while outsiders cannot
Week 4: Create and persistently mount a new filesystem through /etc/fstab and install and remove a package, explaining each step to a study partner or in writing
Week 6: Demonstrate a cron-scheduled script that runs unattended and produces verifiable output, and explain every line of the script
Week 8: Score at least 75 percent overall on the timed practice set with no domain below 60 percent, and complete the final readiness report