3 Shell & command line

20 entries match these filters

• 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 · Concept · 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 · Concept · Linux, macOS 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 · Concept · Linux, macOS Article Basics 15 Oct 2026
• 0052 Slice and summarize text with grep, sort, uniq, cut, awk and sed A handful of classic tools can filter, count, extract and rewrite text right in the terminal. This guide shows the patterns you… Intermediate · How-to · Linux, macOS Article Finding files & text · Text processing 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 · How-to · Linux, macOS, Windows Article Keys & config 15 Oct 2026
• 0054 Fix: Permission denied (publickey) The server refused every key your SSH client offered. Find out which key was offered, make sure its public half is on… Intermediate · Fix · Linux, macOS, Windows Article Keys & config 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 · Reference · Linux, macOS Article Basics · Command-line tools 15 Oct 2026
• 0058 Safe bash script template with set ‑euo pipefail and trap A starting point for bash scripts that stops on errors, rejects unset variables, cleans up temp files on exit and parses options.… Intermediate · Reference · Linux, macOS Script Shell scripting 15 Oct 2026
• 0059 Incremental snapshot backups with rsync A bash script that copies a folder into dated snapshots with rsync, hard-links unchanged files to the previous snapshot to save space,… Advanced · How-to · Linux, macOS Script Backups & syncing · Shell scripting 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 · How-to · Linux, macOS Script Finding files & text · Text processing 15 Oct 2026
• 0061 Fix: Address already in use (free a busy port) Your server cannot start because another process already listens on its port. This script shows which process holds the port and stops… Intermediate · Fix · Linux, macOS Script Processes & ports · Shell scripting 15 Oct 2026
• 0062 ripgrep (rg): fast recursive search ripgrep is a line-oriented search tool that recursively searches the current directory for a regex pattern, skipping ignored, hidden and binary files… Linux, macOS, Windows Repo Command-line tools 15 Oct 2026
• 0063 fzf: command-line fuzzy finder fzf is an interactive fuzzy finder for the terminal. Pipe any list into it, type a few letters, and pick the item… Linux, macOS, Windows Repo Command-line tools 15 Oct 2026
• 0064 jq: command-line JSON processor jq is a small command-line tool for reading, filtering and transforming JSON, like sed and awk for structured data. Linux, macOS, Windows Repo Command-line tools · jq & JSON on the command line 15 Oct 2026
• 0065 ShellCheck: static analysis for shell scripts ShellCheck reads your bash or sh scripts and points out bugs, quoting mistakes and portability problems before you run them. Linux, macOS, Windows Repo Command-line tools 15 Oct 2026
• 0066 fd: a simple, fast alternative to find fd finds files by name with short, friendly syntax and sensible defaults, such as ignoring hidden files and .gitignore entries. Linux, macOS, Windows Repo Command-line tools 15 Oct 2026
• 0076 jq recipes: 23 one-liners for JSON on the command line A runnable collection of jq filters for everyday JSON work: pick fields, filter with select, reshape, sort, count, group, pass shell variables,… Intermediate · Reference · Linux, macOS, Windows Script Command-line tools · jq & JSON on the command line 15 Oct 2026
• 0186 Fix: Ansible UNREACHABLE! Failed to connect to the host via ssh Ansible could not open an SSH session to the host, so no task ran. The text after the colon tells you why:… Intermediate · Fix · Linux, macOS Article Ansible · SSH & servers 15 Oct 2026
• 0254 Automate three servers with Ansible: roles, templates, Vault and safe dry runs Build a real Ansible project for two web servers and one database server: inventory groups, SSH keys, roles, templates, handlers, an encrypted… Intermediate · Tutorial · Linux, macOS Article Ansible · Keys & config 15 Oct 2026
• 0265 Turn a one-liner into a robust bash script: strict mode, options, logging, traps, locking and a schedule Grow a find-and-gzip one-liner step by step into a dependable bash script with strict mode, getopts, usage text, logging, error traps, dry-run,… Intermediate · Tutorial · Linux, macOS Article Services & systemd · Shell scripting 15 Oct 2026