Array
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📦 What is an array? An array is a variable that can store multiple values under one name. ⚠️ Arrays are supported in Bash, not in very old sh. 🔹…
switch command
🔀 What is switch case? In shell scripting, switch case is written as case.It is used to match a value against multiple patterns. 🔹 Syntax Example 3: Check character type…
condition
What is test command? The test command is used to check conditions and return true or false.It’s mainly used in shell scripts and if statements. 👉 It does not print…
🆚 Difference Between vi and nano Editor (Linux / Unix)
📊 Comparison Table Feature vi editor nano editor Difficulty Hard to learn 😵 Very easy 😊 Editing style Mode-based Direct typing Modes Command, Insert, Visual No modes On-screen help ❌…
📝 Nano Editor (Linux / Unix)
Nano is a super simple, beginner-friendly terminal text editor. 🔹 How to open nano Example: 🔹 Nano screen layout ^ means CtrlExample: ^O = Ctrl + O 🔹 Most useful…
vi Editor – Visual editor
Introduction The vi editor is a screen-oriented, full-screen text editor used in UNIX and Linux operating systems. It is one of the oldest and most powerful text editors, designed to…
🐧 History of Linux
🌱 Origins (Before Linux) 🚀 Birth of Linux (1991) 📌 Important:Linux = Kernel, not the complete operating system. 🧩 GNU + Linux = Complete OS 📦 Growth of Linux Distributions…
Working with columns and fieldscut, paste, join
✂️ cut – Extract Columns (Fields) from a File What it does Extracts specific columns/fields from each line. Syntax Examples File: emp.txt ⚠️ Note: cut works best with single, consistent…
What are grep, fgrep, egrep?[Pattern Matching Command]
What are grep, fgrep, egrep? 1️⃣ grep – General Pattern Search (Basic Regular Expressions) 1)grep command:-(global regular expression print) Syntax Example 🔹 Searches lines containing unix Using regex 🔹 Lines…
UNIX Architecture
UNIX Architecture is layer-based, meaning each layer has a specific role and interacts with others in a structured way. 🔹 Layers of UNIX Architecture 1️⃣ Hardware 2️⃣ Kernel (Heart of…