Linux Command Line Bootcamp: From Beginner to Advanced :20hr

• Timestamp updating, blank file creation with touch, and nested directories with mkdir -p.

• Quick editing with nano and modal text manipulation in vi (Command vs. Insert mode, :wq).

• File concatenation, forward/backward paging with less, and top/bottom inspection with head and tail.

• Standard stream descriptors (0, 1, 2), piping, overwriting (>), and appending (>>).

• Using mv to rename items and reposition files across the filesystem.

• Copying individual items, batch copies, and recursive directory tree replication (cp -r).

• Safely removing files (rm), interactive verification (rm -i), and recursive folder removal (rm -rf).

• Inode architecture, creating symbolic/soft links (ln -s), and permanent hard links (ln).

• Root privileges, security implications of UID 0, switching accounts (su), and elevation policies.

• User skeletons, default profile seeding, and home directory auto-population.

• Assigning secure user passwords via passwd and locking unverified accounts.

• Modifying account details, comments, and shells using usermod.

• Moving user home directories (usermod -d -m) and updating default login shells.

• Setting password expiration, account lockouts, and aging policies with chage.

• Locking user logins, cleaning up processes, and deleting user accounts and home files (userdel -r).

• The sudo architecture, editing /etc/sudoers safely with visudo, and group privilege grants.

• Standard Unix permission triads (rwx), user/group/other bits, and directory execute significance.

• Changing user and group owners on files and nested directories.

• Adding users to supplementary groups with usermod -aG and auditing user group lists.

The Set User ID bit, executing with owner privileges, security vulnerabilities, and chmod u+s.

• Shared team directories with SGID, directory deletion protection with the Sticky Bit (/tmp).

• Going beyond standard POSIX permissions: checking fine-grained permissions using getfacl.

• Applying, modifying, and revoking granular user and group ACL rules with setfacl.

• Setting immutable flags (+i), append-only restrictions (+a), and verifying with lsattr.

• System clocks, formatted date strings, time zone adjustments, and hardware clocks.

Inode numbers, access (atime), modify (mtime), and change (ctime) timestamps with stat.

• Word, line, and byte counting; alphabetical/numerical sorting; identifying and deduplicating lines.

• Searching files by name, extension, file type, and path wildcards.

• Searching by size, modification times, permissions, and running batch commands via -exec.

Pattern matching, recursive directory search, line numbering (-n), and inverted matches (-v).

• Line anchors (^, $), wildcard dots (.), and literal character escaping.

• Bracket character classes [a-z], negation [^0-9], and multiplier ranges {n,m}.

• Translating lowercase to uppercase, squeezing repeat characters, and deleting character classes.

The stream editor engine: basic pattern substitutions (s/pattern/replacement/g).

• Modifying files directly (sed -i), selective line addressing, and deleting matched lines.

• Columnar data parsing, positional variables ($1, $2), custom delimiters (-F), and pattern filters.

• Record counts (NR), field totals (NF), arithmetic operations, and formatting clean reports.

• Converting standard stream input into command arguments safely with xargs -0.

• Compressing and expanding single files with gzip and gunzip, viewing contents via zcat.

• Creating uncompressed tarballs (tar -cvf), listing contents (-tvf), and extracting (-xvf).

• Maintaining system permissions, exclusion lists, and incremental archives.

• Compression ratios and CPU performance across .tar.gz, .tar.bz2, and .tar.xz.

• Handling Windows/cross-platform archive packages with zip, unzip, and p7zip.

• Differential file synchronization, archive flags (-avz), and trailing slash path nuances.

• Deleting extraneous target files (--delete), progress reporting, and dry runs (--dry-run).

• Logging into remote machines, running SSH commands, and streaming rsync backups over encrypted SSH.

• Crontab timing syntax (Minute, Hour, Day, Month, Day of Week), paths, and user crontabs (crontab -e).

System-wide cron directories (/etc/cron.*), environment issues, and logging cron output.

Running periodic tasks on laptops and workstations that are not powered on 24/7.

Enqueuing delayed single-run commands with at, monitoring the queue with atq, and deleting jobs with atrm.

• Writing an automation script and defining a custom .service unit under /etc/systemd/system/.

• Writing a corresponding .timer unit, monotonic vs. realtime clocks, enabling and monitoring timer triggers.

• Process trees, PIDs, PPIDs, and process state codes using ps aux and ps -ef.

Navigating the real-time resource monitor: CPU states, memory usage, load averages, and sorting processes.

• Interacting with running tasks in top: renicing priorities, sending kill signals, and saving display configurations.

Understanding niceness values (-20 to 19), launching low/high priority jobs, and altering running processes.

• Sending signals: SIGTERM (15), SIGKILL (9), SIGHUP (1), and killing tasks by name.

• Backgrounding tasks with &, suspending processes with Ctrl+Z, and managing tasks via jobs, fg, and bg.

Creating persistent sessions, detaching without killing running scripts, and reattaching (screen -r).

• Split windows, multi-screen navigation, and managing locked sessions.

• The Tmux prefix key (Ctrl+b), session naming, creating windows, and detaching.

• Splitting terminals horizontally and vertically into panes, resizing panes, and cycling focus.

• Customizing shortcut keybindings, mouse support, and appearance settings in ~/.tmux.conf.

Custom status bar clocks, battery meters, custom colors, and reloading configs instantly.

• Sharing a single terminal session between two local or SSH users for live collaboration and pair-programming.