Introduction to Shell Scripting: Automating Daily Tasks (Bash and PowerShell Edition)#

Alright, imagine this: you wake up, fire up your computer, and instead of wasting time organizing files or backing up data, you just hit a button, and boom—your computer does all that boring stuff for you. That’s the magic of shell scripting. It’s not just for Linux nerds; even Windows folks can automate tasks like a pro using PowerShell.

Let’s break this down step-by-step, keeping things chill and beginner-friendly. We’ll cover Bash for Linux/macOS and PowerShell for Windows. No rocket science, just automation magic.

Part 1: What’s a Shell Script?#

A shell script is a set of instructions you write in a text file, and the computer runs them, just like how a playlist makes Spotify play the songs you want.

For Linux/macOS, we use Bash (Bourne Again Shell). For Windows, we have PowerShell. Both are built-in tools that make automation super easy once you know the basics.

Part 2: Getting Started with Bash (Linux/macOS)#

Step 1: Open the Terminal#

Hit CTRL+ALT+T (Linux) or search for Terminal (macOS).

Step 2: Create Your First Script#

In your terminal, type:

nano hello.sh

This opens a text editor. Inside, write:

#!/bin/bash
echo "Hello from Bash!"

Step 3: Save and Exit#

Press CTRL+O to save, ENTER to confirm, then CTRL+X to exit.

Step 4: Make It Executable#

Run this to give your script permission to run:

chmod +x hello.sh

Step 5: Execute the Script#

Run your script by typing:

./hello.sh

You should see:

Hello from Bash!

Part 3: Getting Started with PowerShell (Windows)#

Step 1: Open PowerShell#

Search for PowerShell in the Start menu and open it.

Step 2: Create Your First Script#

Open Notepad (yes, Notepad), and type:

Write-Output "Hello from PowerShell!"

Step 3: Save as a .ps1 File#

Go to File > Save As, name it hello.ps1, and choose “All Files” in the save dialog. Make sure it ends with .ps1, like this:

hello.ps1

Step 4: Run the Script#

Back in PowerShell, navigate to where you saved the file (use cd to change directories). Then, run:

./hello.ps1

You should see:

Hello from PowerShell!

Part 4: Real-Life Automation with Shell Scripts#

Now that you know the basics, let’s tackle some useful scripts.

1. Organize Files#

Bash (Linux/macOS):

#!/bin/bash
mkdir -p Pictures
mv *.jpg Pictures/
echo "JPG files moved to Pictures!"

PowerShell (Windows):

New-Item -ItemType Directory -Path . -Name "Pictures"
Move-Item *.jpg Pictures/
Write-Output "JPG files moved to Pictures!"

2. Automate Backups#

Bash (Linux/macOS):

#!/bin/bash
rsync -av ~/Documents ~/Backup
echo "Backup complete!"

PowerShell (Windows):

Copy-Item -Path C:\Users\YourName\Documents -Destination D:\Backup -Recurse
Write-Output "Backup complete!"

3. Monitor System Performance#

Bash (Linux/macOS):

#!/bin/bash
while true; do
  echo "$(date): $(top -b -n1 | head -5)" >> system.log
  sleep 3600
done

PowerShell (Windows):

while ($true) {
  Get-Date | Out-File -Append -FilePath system.log
  Get-Process | Sort-Object CPU -Descending | Select-Object -First 5 | Out-File -Append -FilePath system.log
  Start-Sleep -Seconds 3600
}

Part 5: Scheduling Scripts#

On Linux/macOS:#

Use crontab to run scripts at specific times:

  1. Open crontab:

    crontab -e

  2. Add a line to run your script every day at 8 AM:

    0 8 * * * /path/to/your/script.sh

On Windows:#

Use Task Scheduler:

  1. Open Task Scheduler (search for it in Start).
  2. Create a new task.
  3. Set a trigger (e.g., daily at 8 AM).
  4. Set an action to run your .ps1 script using PowerShell.

Part 6: Tips for Success#

  1. Test Small: Start with tiny scripts and gradually add more features.
  2. Use Comments: Add # in Bash or # in PowerShell to explain what each part does.
  3. Handle Errors: Check if files exist before moving them to avoid errors.
  4. Experiment: Don’t be afraid to break things (in a safe environment).

Wrapping Up#

Whether you’re using Bash or PowerShell, shell scripting is your ticket to automating the boring stuff. It saves time, reduces errors, and makes you look like a tech wizard to your friends.

Start small, stay curious, and soon you’ll be automating tasks you never thought possible. Now, go script something awesome!

[Crusveder]