Linux and the Command Line for Developers

Contents

Every lesson has the same steps: what it is, how it works, a real example, common mistakes, then interview questions with answers you can say out loud.

1. Lesson 00The Terminal, the Shell and the Linux File SystemWhat the shell is, moving around, the directory layout, absolute and relative paths, reading files, and the commands you will use hourly.12 min
2. Lesson 01Users, Permissions and OwnershipUsers and groups, reading rwx and octal modes, chmod and chown, sudo, umask, setuid in plain words, and common permission mistakes.13 min
3. Lesson 02Processes, Signals and Job ControlWhat a process is, ps and top, foreground and background jobs, signals such as SIGTERM and SIGKILL, exit codes, and zombies and orphans.14 min
4. Lesson 03Pipes, Redirection and Text Tools: grep, sed, awk, find and xargsstdin, stdout and stderr, pipes, redirection, the text tools used to search and reshape data, and real one-line recipes.15 min
5. Lesson 04Shell Scripting: Variables, Conditions, Loops and FunctionsWriting safe bash scripts: quoting, set -euo pipefail, arguments, conditions, loops, functions, trap, and ShellCheck.15 min
6. Lesson 05SSH, Networking Commands and Transferring FilesSSH keys and config, scp and rsync, port forwarding, curl, ss, dig, ping and traceroute, and what each tells you.14 min
7. Lesson 06Packages, Services, Cron and systemdapt and other package managers, running a service with systemd, reading unit files, journalctl, cron and systemd timers.14 min
8. Lesson 07Disks, Memory, Logs and Troubleshooting a Slow Serverdf, du, free, load average, iostat-style tools, reading logs, and a step-by-step method for a slow or full server.15 min
9. Lesson 08Linux and Shell Interview Questions With Model AnswersPermissions, processes, pipes, scripting and troubleshooting questions with model answers.14 min