5.1.8. Explain the basics of scripting. (Obj. 4.8)

💡 First Principle: Scripting automates repetitive tasks, improving efficiency and reducing the potential for human error. If you do something more than twice, script it.

At its core, a script is just a simple computer program written as a plain text file. It contains a series of commands that are executed in sequence by an interpreter. The power of scripting is automation. If you find yourself performing the same set of command-line tasks over and over again, you can put those commands into a script and then run the script with a single command. This saves time, ensures the task is performed exactly the same way every time (reducing errors), and allows non-technical users to perform complex tasks.

Script Types Quick Reference:

Figure: PowerShell 7.5 running in Windows Terminal - the modern automation framework for Windows administration

Deep Dive: Script Language Characteristics

• Batch files (.bat): The original scripting language for Windows. Uses DOS-style commands like copy, del, echo. Simple but limited - no objects, weak error handling. Still useful for quick tasks.

• PowerShell (.ps1): The modern Windows automation framework. Key insight: PowerShell works with objects, not text. When you run Get-Process, you get process objects with properties like .CPU and .Memory, not just lines of text. This makes it incredibly powerful for system administration.

  Critical Security Feature: By default, PowerShell will NOT run scripts (execution policy is Restricted). You must explicitly change this using Set-ExecutionPolicy. Common policies:

  • Restricted - No scripts run (default)
  • RemoteSigned - Downloaded scripts must be signed; local scripts run freely
  • Unrestricted - All scripts run (dangerous)

• Shell script (.sh): The standard for Linux and macOS. Runs in Bash or other shells. The first line (#!/bin/bash) tells the system which interpreter to use - this is called the shebang.

• Python (.py): Readable, powerful, cross-platform. Excellent for complex logic, data manipulation, and when you need libraries (e.g., for working with APIs, Excel files, or databases).

• JavaScript (.js): Primarily for web browsers, but Node.js allows server-side execution. Used for web automation and modern tooling.

Practical Examples:

Batch File - Map Network Drives:

@echo off
REM Map sales department drives
net use S: \\FILESRV01\Sales /persistent:yes
net use T: \\FILESRV01\TeamDocs /persistent:yes
net use P: \\FILESRV01\Public /persistent:yes
echo All drives mapped successfully!
pause

PowerShell - System Health Check:

# Get disk space on C: drive (objects, not text!)
$disk = Get-WmiObject Win32_LogicalDisk -Filter "DeviceID='C:'"
$freeGB = [math]::Round($disk.FreeSpace / 1GB, 2)
$totalGB = [math]::Round($disk.Size / 1GB, 2)
$percentFree = [math]::Round(($disk.FreeSpace / $disk.Size) * 100, 1)

Write-Host "C: Drive: $freeGB GB free of $totalGB GB ($percentFree% free)"

if ($percentFree -lt 10) {
    Write-Host "WARNING: Low disk space!" -ForegroundColor Red
}

Shell Script (Linux) - Clear Temp Files:

#!/bin/bash
# Clear temporary files older than 7 days
echo "Cleaning temp files..."
find /tmp -type f -mtime +7 -delete
echo "Done! Cleaned files older than 7 days."

Common Use Cases for Help Desk:

• User onboarding: Map drives, install standard software, configure printers
• Maintenance: Clear temp files, check disk space, restart services
• Reporting: Gather system info, check for updates, audit installed software
• Troubleshooting: Reset network settings, clear caches, repair common issues

Technician's Insight: You don't need to be a programmer, but you should be able to:

1. Identify script types by extension
2. Understand what a script is doing at a high level
3. Modify existing scripts (change a path, add a command)
4. Know the security implications (especially PowerShell execution policy)

Reflection Question: A user double-clicks a .ps1 file and nothing happens. What is the most likely cause, and how would you enable them to run it safely?