🐚Linux Shell Essentials
Stop copy-pasting shell commands you don't understand. Build the mental model of files, processes, and pipes — then compose grep, awk, and xargs into a maintenance script with real error handling.
Phase 1Files, Processes, and the Unix Philosophy
Build the mental model of files, processes, and pipes
Everything is a file, even the things that aren't
6 minEverything is a file, even the things that aren't
Every command is a process with three open files
7 minEvery command is a process with three open files
A pipe is two processes sharing a kernel buffer
7 minA pipe is two processes sharing a kernel buffer
Your shell is always standing somewhere
6 minYour shell is always standing somewhere
Phase 2Composing Daily Tasks with Pipes, Grep, Awk, and Xargs
Wield grep, awk, sed, and xargs for daily tasks
Grep is a filter, not a search engine
6 minGrep is a filter, not a search engine
Awk is grep that knows about columns
7 minAwk is grep that knows about columns
Sed is awk's older sibling who only edits
6 minSed is awk's older sibling who only edits
Xargs turns lines of input into command arguments
6 minXargs turns lines of input into command arguments
Find is a filesystem query language pretending to be a command
7 minFind is a filesystem query language pretending to be a command
Phase 3Permissions, Redirection, and Process Substitution in Practice
Connect permissions, redirection, and process substitution
An rwx triple isn't a permission — it's three of them
6 minAn rwx triple isn't a permission — it's three of them
Redirection is wiring, not syntax
7 minRedirection is wiring, not syntax
Process substitution lets a command pretend to be a file
7 minProcess substitution lets a command pretend to be a file
Quoting isn't decoration — it's the difference between one word and many
6 minQuoting isn't decoration — it's the difference between one word and many
Phase 4Ship a Maintenance Script with Real Error Handling
Write a maintenance script with proper error handling
Build a log-rotating, error-aware maintenance script
8 minBuild a log-rotating, error-aware maintenance script
Frequently asked questions
- What's the difference between a pipe and redirection in the shell?
- This is covered in the “Linux Shell Essentials” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
- Why do shell scripts need 'set -euo pipefail' at the top?
- This is covered in the “Linux Shell Essentials” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
- How do file permissions actually work with chmod numbers like 755?
- This is covered in the “Linux Shell Essentials” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
- When should I use awk versus sed versus grep?
- This is covered in the “Linux Shell Essentials” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
- What is process substitution and when do I need it?
- This is covered in the “Linux Shell Essentials” learning path. Start with daily 5-minute micro-lessons that build from fundamentals to hands-on application.
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