Easy Shell: A Beginner’s Guide to Shell Scripting

Easy Shell Cookbook: Quick Scripts for Everyday Tasks

Overview:
A compact, practical guide focused on short, reusable shell scripts that solve common daily tasks across Unix-like systems. Emphasizes readability, portability, and safety for beginners and intermediate users.

Key sections

1. Getting started

   • Shell basics (bash, sh, zsh)
   • Script structure, shebang, permissions
   • Best practices: quoting, error handling, set -euo pipefail

2. File and text handling

   • Batch renaming, file backups, safe deletions
   • Grep/sed/awk recipes for parsing logs and CSVs
   • Simple text transformations and reports

3. System maintenance

   • Disk usage summaries, log rotation helpers
   • Automated backups and pruning old files
   • Service checks and restart scripts

4. Networking and downloads

   • Simple wget/curl download managers
   • Querying APIs with jq, automating uploads
   • Local network scans and port checks

5. Automation and scheduling

   • Cron job examples and idempotent scripts
   • Locking to prevent concurrent runs
   • Using systemd timers as alternatives

6. Developer utilities

   • Quick build/test runners, cleanup scripts
   • Simple deploy helpers and git automation snippets

7. Cross-platform tips

   • POSIX-compatible constructs vs. Bash-specific features
   • Handling differences between macOS and Linux

8. Safety and testing

   • Dry-run modes, verbose logging, exits codes
   • Minimal test harnesses and examples

Example recipes (brief)

• Backup a directory with timestamp:

bash
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#!/usr/bin/env bash
set -euo pipefail src=“\(1</span><span class="token" style="color: rgb(163, 21, 21);">"</span><span> </span><span></span><span class="token assign-left" style="color: rgb(54, 172, 170);">dest</span><span class="token" style="color: rgb(57, 58, 52);">=</span><span class="token" style="color: rgb(163, 21, 21);">"/backup/</span><span class="token" style="color: rgb(54, 172, 170);">\)(basename ”\(src</span><span class="token" style="color: rgb(54, 172, 170);">"</span><span class="token" style="color: rgb(54, 172, 170);">)</span><span class="token" style="color: rgb(163, 21, 21);">-</span><span class="token" style="color: rgb(54, 172, 170);">\)(date +%Y%m%d-%H%M%S”).tar.gz”
tar -czf “\(dest</span><span class="token" style="color: rgb(163, 21, 21);">"</span><span> -C </span><span class="token" style="color: rgb(163, 21, 21);">"</span><span class="token" style="color: rgb(54, 172, 170);">\)(dirname ”\(src</span><span class="token" style="color: rgb(54, 172, 170);">"</span><span class="token" style="color: rgb(54, 172, 170);">)</span><span class="token" style="color: rgb(163, 21, 21);">"</span><span> </span><span class="token" style="color: rgb(163, 21, 21);">"</span><span class="token" style="color: rgb(54, 172, 170);">\)(basename “\(src</span><span class="token" style="color: rgb(54, 172, 170);">"</span><span class="token" style="color: rgb(54, 172, 170);">)</span><span class="token" style="color: rgb(163, 21, 21);">"</span><span> </span><span></span><span class="token builtin" style="color: rgb(43, 145, 175);">echo</span><span> </span><span class="token" style="color: rgb(163, 21, 21);">"Saved: </span><span class="token" style="color: rgb(54, 172, 170);">\)dest”

• Remove files older than 30 days:

bash
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find /tmp/myapp -type f -mtime +30 -print -delete 

• Simple API request and parse JSON:

bash
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curl -s ‘https://api.example.com/data’ | jq -r ’.items[] | “(.id): (.name)”’

Who it’s for

• Beginners who want practical, copy-pasteable scripts.
• Intermediate users seeking idiomatic, safe patterns.
• DevOps and sysadmins needing quick reference snippets.

Outcome

Readers gain a toolbox of concise, tested scripts to automate routine tasks, reduce manual work, and learn safer shell practices.