Bash — Shell Scripting

Argument parsing

#!/bin/bash
while [[ $# -gt 0 ]]; do
    case $1 in
        -n|--name) name="$2"; shift 2 ;;
        -a|--age) age="$2"; shift 2 ;;
        *) echo "Unknown: $1"; shift ;;
    esac
done

Error handling

#!/bin/bash
set -euo pipefail

trap 'echo "Error on line $LINENO"' ERR

Logging

#!/bin/bash
LOG_FILE="app.log"

log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

log "Starting script"
log "Processing files"

Main function

#!/bin/bash
main() {
    echo "Starting..."
    # Do work
    echo "Done!"
}

main "$@"

Mini Practice

Write Bash code that:

1. Parses command-line arguments
2. Sets up error handling with trap
3. Creates a logging function
4. Uses a main function pattern

Up Next

In the next lesson, you'll learn about Cron Jobs — scheduled tasks.