Wrap-up and resources
Key Takeaways
- Linux is a kernel and a system: Only the kernel touches hardware; a distribution bundles it with tools.
- Know where you are before acting:
pwdandlsbefore any copy, move or delete; deletion is final. - Nine letters govern a file: three for the owner, three for the group, three for others;
chmod u+xmakes your script runnable. - Three doors on every command:
>rewrites,>>appends,2>catches errors, and|feeds one command's output to the next. - Emacs: buffer, region, kill ring:
C-galways rescues you, andM-xopens every command by name. - vi: think in modes:
Escreturns to command mode,itypes,:wqsaves and exits. - The cloud sandbox is temporary: Push your work to Git before ending the session.
- Ask after you have tried: Problem, Signal, Tiny guess, Ask, and the assistant is a coach, not an executor.
Glossary
| Term | Definition | Part |
|---|---|---|
| Kernel | The program managing CPU, memory, files and devices | 1 |
| Distribution | Kernel + tools + package manager + defaults | 1 |
| System Call | A request a program makes to the kernel for a service | 1 |
| Shell | A program that reads and runs your text commands | 2 |
| Absolute path | A path starting from the root / | 2 |
| Relative path | A path starting from the current directory | 2 |
| man page | The official documentation of a command, opened with man | 2 |
| Permissions | Nine rwx letters for three classes: owner, group, others | 3 |
| chmod | The command that changes a file's permissions by letters or numbers | 3 |
| Redirection | Sending a command's output or errors to a file instead of the screen | 4 |
| Pipe | Making one command's output the next command's input directly | 4 |
| Buffer | An in-memory copy of a file inside Emacs | 5 |
| Kill ring | The list of cut texts in Emacs | 5 |
| Mark / Region | A position you set and the text between it and the cursor | 5 |
| Command mode | The vi mode where keys act as commands | 6 |
| Insert mode | The vi mode where keys type text | 6 |
| Integrated terminal | A shell inside the VS Code window | 7 |
| Extension | A package that adds capabilities to VS Code | 7 |
| Sandbox | A temporary isolated environment for experimenting | 7 |
| Prompt formula | Problem, Signal, Tiny guess, Ask | 8 |
| find | Finds files by name, type, size and date. | 9 |
| grep | Searches for text or a pattern inside files. | 9 |
| PID | The number identifying each running process. | 9 |
| shebang | The first line #!/usr/bin/env bash naming the interpreter. | 10 |
| $1 | The first argument passed to the script. | 10 |
| $? | The last command's exit code: 0 is success. | 10 |
| cmdlet | A PowerShell command in Verb-Noun form, like Get-Process. | 11 |
| Get-Member | Shows the properties and methods of objects in the pipeline. | 11 |
| $_ | The current object inside Where-Object or ForEach-Object. | 11 |
Sources
The best outside resources for these lessons, classified by kind and level. All are open to everyone and need no account on any platform. Use the filters to narrow the list.
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Video (3)
VideoLinux Operating System: Crash Course (freeCodeCamp)The file system, commands, permissions and the shell in one sitting.youtube.comBeginnerVideoVim Tutorial for Beginners (freeCodeCamp)Modes, motions and editing, enough to be comfortable in vi on any server.youtube.comBeginnerVideoGit and GitHub for Beginners: Crash Course (freeCodeCamp)Commits, branches, merges and pull requests shown live.youtube.comBeginner
Interactive tools (5)
Interactive toolexplainshellPaste any command and it explains each part from the manual pages.explainshell.comBeginnerInteractive tooltldr pagesShort, example-first summaries instead of long man pages.tldr.shBeginnerInteractive toolOpenVimAn interactive in-browser lesson that teaches modes and motions by doing.openvim.comBeginnerInteractive toolVim AdventuresA game where you learn vi motions and commands as you clear levels.vim-adventures.comBeginnerInteractive toolLearn Git BranchingA game that draws your repository as a graph while you type Git commands.learngitbranching.js.orgBeginner
Official documentation (28)
Official docsThe Linux kernel documentationThe official kernel reference: how it is organised and what it offers programs.kernel.orgIntermediateOfficial docsThe list of system callsThe manual page listing the system calls programs make to the kernel.man7.orgIntermediateOfficial docsUbuntu Server documentationThe distribution your cloud sandbox runs, with installation and administration guides.ubuntu.comBeginnerOfficial docsThe GNU Coreutils manualThe precise reference for ls, cp, mv, rm, mkdir and the rest, with every option.gnu.orgBeginnerOfficial docsHow paths are resolvedA manual page explaining absolute and relative paths and how “..” works, precisely.man7.orgIntermediateOfficial docsThe GNU Emacs manualThe full reference: buffers, the region, the kill ring and commands.gnu.orgBeginnerOfficial docsThe Emacs reference cardOne page of the key shortcuts to print or pin beside your screen.gnu.orgBeginnerOfficial docsVim help on the webThe official Vim docs in searchable form, covering the vi commands too.vimhelp.orgIntermediateOfficial docsThe POSIX vi specificationThe official vi specification: what every conforming system guarantees.pubs.opengroup.orgAdvancedOfficial docsThe VS Code user interfaceThe official tour of the interface: activity bar, explorer and bottom panel.code.visualstudio.comBeginnerOfficial docsKeyboard shortcutsHow to view and change shortcuts, with the command palette at the centre.code.visualstudio.comBeginnerOfficial docsThe integrated terminalThe basics of the terminal inside the editor and how it follows your workspace folder.code.visualstudio.comBeginnerOfficial docsLinux shortcut cardThe official shortcut sheet as a PDF.code.visualstudio.comBeginnerOfficial docsPrompt engineering overviewHow to write a clear, specific request that gets a sharper answer.docs.anthropic.comBeginnerOfficial docsThe rm manual pageRead it before running any delete command the assistant suggests.man7.orgBeginnerOfficial docsThe Linux Kernel Archives, About Linux KernelAn official reference covering the topic precisely.kernel.orgAdvancedOfficial docsman7.org, intro(1): introduction to user commandsThe official man page for intro(1): exact syntax, options and behaviour.man7.orgIntermediateOfficial docsman7.org, ls(1)The official man page for ls(1): exact syntax, options and behaviour.man7.orgIntermediateOfficial docsman7.org, cp(1)The official man page for cp(1): exact syntax, options and behaviour.man7.orgIntermediateOfficial docsman7.org, pwd(1)The official man page for pwd(1): exact syntax, options and behaviour.man7.orgIntermediateOfficial docsGNU, A Guided Tour of EmacsOfficial documentation from the GNU project.gnu.orgIntermediateOfficial docsGNU Emacs Manual, Basic Editing CommandsOfficial documentation from the GNU project.gnu.orgIntermediateOfficial docsGNU Emacs Manual, The Mark and the RegionOfficial documentation from the GNU project.gnu.orgIntermediateOfficial docsVim User Manual, About the manual (usr_01)An official reference covering the topic precisely.neo.vimhelp.orgIntermediateOfficial docsVim User Manual, The first steps in Vim (usr_02)An official reference covering the topic precisely.neo.vimhelp.orgIntermediateOfficial docsvim.org, DocumentationAn official reference covering the topic precisely.vim.orgIntermediateOfficial docsVisual Studio Code, Tips and TricksAn official reference covering the topic precisely.code.visualstudio.comIntermediateOfficial docsDartmouth CS 50, Debugging lecture notesAn official reference covering the topic precisely.cs.dartmouth.eduIntermediate
Articles and explainers (8)
ArticleWhat is free software?The GNU project's definition of the four freedoms, the root of open source in the Linux world.gnu.orgBeginnerArticleThe official GNU Emacs pageNews, downloads and ways to learn, straight from the GNU project.gnu.orgBeginnerArticleThe Prompt Engineering GuideAn open guide to prompting techniques, with examples.promptingguide.aiIntermediateArticleHow to ask a good questionOld, still-valid rules: summarise, include the error, show what you tried. They apply to the assistant too.stackoverflow.comBeginnerArticlesDigitalOcean, Basic Linux Navigation and File ManagementAn article explaining the topic with examples and clear steps.digitalocean.comIntermediateArticlesLinuxConfig, Filesystem basicsAn article explaining the topic with examples and clear steps.linuxconfig.orgIntermediateArticlesAnthropic, Best practices for prompt engineeringAn article explaining the topic with examples and clear steps.claude.comIntermediateArticlesDigitalOcean, Prompt Engineering Best PracticesAn article explaining the topic with examples and clear steps.digitalocean.comIntermediate
Resources for this lesson
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