Unix Shell Programming 📌 ⏰

if-then-else , case statements for decision-making. Loops: for , while loops to repeat tasks. Input/Output Redirection & Pipes: > : Redirect output (overwrite file). >> : Append output.

#!/bin/bash # This is a comment echo "Starting Script..." # Define a variable FILE_NAME="backup.txt" # Create a file touch $FILE_NAME # List files and save to a report ls -l > $FILE_NAME echo "File list saved to $FILE_NAME" Use code with caution. Copied to clipboard 5. Steps to Create and Run a Script

A Unix shell is a command-line interpreter that acts as an interface between the user and the operating system. Shell programming (or scripting) involves writing a series of commands in a plain text file, which the shell executes sequentially. It enables automation of repetitive tasks, system management, and complex data processing. 2. Key Components of Shell Scripts Unix Shell Programming

Use a text editor like vi or nano to create a file, e.g., script.sh .

Quote variables to prevent issues with spaces, e.g., "$variable" . if-then-else , case statements for decision-making

grep (search), sed (stream editor), awk (data manipulation), cat (view content), cut , sort .

Used to store data. In shell, all variables are treated as strings. Example: name="John" ; echo $name (access variable with $ ). Control Structures: >> : Append output

ps (view processes), kill (terminate process). Arithmetic: expr or $((expression)) for calculations. 4. Basic Structure of a Shell Script