3 Shell & command line

22 entries match these filters

• 0418 Bash scripting fundamentals: variables, conditions, loops, functions The core building blocks of a bash script: variables and quoting, if and test, for and while loops, functions, exit codes and… Beginner · Explains an idea · Linux, macOS Article Basics · Shell scripting 15 Oct 2026
• 0423 Fix: bad interpreter or command not found after a script is copied from Windows (CRLF) A script edited on Windows carries invisible carriage returns, so Linux looks for /bin/bash^M. How to spot CRLF line endings, convert them… Beginner · Fixes an error · Linux, macOS, Windows Article Basics · Shell scripting 15 Oct 2026
• 0425 jq cheat script: pretty-print, filter and flatten JSON from a file or stdin A small read-only bash wrapper around jq with the recipes you keep looking up: pretty, compact, sorted keys, list paths, pick fields,… Beginner · Cheat sheet · Linux, macOS Script jq & JSON on the command line · Modern command-line tools · Text processing 15 Oct 2026
• 0392 Install Visual Studio Code on Linux, macOS and Windows Install VS Code from Microsoft's packages, Homebrew or winget, get the code command working in the terminal, and add the extensions you… Beginner · Step by step · Linux, macOS, Windows Article Command-line tools · Installing languages & tools 15 Oct 2026
• 0345 SSH keys: create, copy and use them Generate an ed25519 key pair, install the public key on a server with ssh-copy-id, keep the private key protected with a passphrase… Beginner · Step by step · Linux, macOS, Windows Article Keys & config · SSH 15 Oct 2026
• 0335 Docker cleanup script with dry run and confirmation A bash wrapper around docker system prune that shows disk usage and lists what would be removed, supports a dry-run flag, and… Beginner · Step by step · Linux, macOS Script Docker basics · Shell scripting 15 Oct 2026
• 0320 Fix: address already in use (EADDRINUSE) Something is already listening on the port your program wants. Find the process with lsof or ss, stop it or pick another… Beginner · Fixes an error · Linux, macOS Article Networking & firewalls · Node.js · Processes & ports 15 Oct 2026
• 0334 Fix: port is already allocated docker run or docker compose up fails with Bind for 0.0.0.0:8080 failed: port is already allocated. Find what holds the port, another… Beginner · Fixes an error · Linux, macOS, Windows Article Docker fixes · Processes & ports 15 Oct 2026
• 0290 What is a cron job? A cron job is a command scheduled to run automatically at set times, such as every night at two o'clock. Beginner · Explains an idea · Any system Article cron & timers 15 Oct 2026
• 0316 Fix: command not found bash: something: command not found means the shell could not find a program with that name in any PATH directory. The usual… Beginner · Fixes an error · Linux, macOS Article Basics · Packages & updates 15 Oct 2026
• 0317 Fix: Permission denied when running a script (chmod +x) bash: ./script.sh: Permission denied means the file exists but you may not execute it. Usually the execute bit is missing; sometimes the… Beginner · Fixes an error · Linux, macOS Article Basics · Users, sudo & hardening 15 Oct 2026
• 0289 What is a process? A process is a running program; the operating system gives each one its own memory and an ID number. Beginner · Explains an idea · Any system Article Processes & ports 15 Oct 2026
• 0284 What is a shell? A shell is the program that reads the commands you type and tells the operating system to run them. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
• 0285 What is a terminal? A terminal is the window where you type commands; the shell inside it does the actual work. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
• 0286 What is PATH? PATH is the list of folders your shell searches to find a program when you type its name. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
• 0287 What is an environment variable? An environment variable is a named value the operating system passes to programs, such as settings or secrets. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
• 0051 Environment variables and PATH Environment variables are named settings that every program inherits from the shell. PATH is the one that tells the shell where to… Beginner · Explains an idea · Linux, macOS Article Basics 15 Oct 2026
• 0057 Shell cheat sheet: everyday commands A quick reference for moving around, managing files, viewing and searching text, checking processes and disk space in bash and zsh, with… Beginner · Cheat sheet · Linux, macOS Article Basics · Command-line tools 15 Oct 2026
• 0053 Set up SSH keys: ssh-keygen, ssh-copy-id and ~/.ssh/config SSH keys let you log in to servers and push to Git hosts without typing a password. Create an ed25519 key, install… Beginner · Step by step · Linux, macOS, Windows Article Keys & config 15 Oct 2026
• 0060 Find the biggest files and folders eating your disk A short bash script that lists the largest files over a size limit and the largest subfolders, using find, du, sort and… Beginner · Step by step · Linux, macOS Script Finding files & text · Text processing 15 Oct 2026
• 0049 Pipes and redirection: connecting commands A pipe sends one command's output into another command, and redirection sends output to a file. Together they let small tools build… Beginner · Explains an idea · Linux, macOS Article Basics · Text processing 15 Oct 2026
• 0050 File permissions: chmod, chown and what 755 means Every file has an owner, a group and read/write/execute permissions for three kinds of users. chmod changes the permissions and chown changes… Beginner · Explains an idea · Linux, macOS Article Basics 15 Oct 2026