Automation and Task Scheduling ⚙️

# ===== save-me.ps1 — your first real PowerShell SCRIPT =====
# A script is just commands saved in a file ending in .ps1.
# Run it by name from a terminal:  .\save-me.ps1

# param() MUST be the first code in the file. It declares inputs the
# caller can pass, so the script is reusable instead of hard-coded.
param(
    [string]$Name = 'world'        # a parameter with a default value
)

Write-Output "Hello, $Name!"       # "$Name" is replaced by the value
Write-Output "Today is $(Get-Date -Format 'yyyy-MM-dd')"

# First run with no argument (uses the default):
PS C:\Scripts> .\save-me.ps1
Hello, world!
Today is 2026-06-15

# Run again, passing a value for -Name:
PS C:\Scripts> .\save-me.ps1 -Name 'Sam'
Hello, Sam!
Today is 2026-06-15

# Windows BLOCKS scripts by default to stop you running malware by accident.
# Out of the box you'll hit this when you try to run save-me.ps1:
#   .\save-me.ps1 : File ... cannot be loaded because running scripts
#   is disabled on this system.

# 1) See the current policy
Get-ExecutionPolicy
# Restricted        <- the default: no scripts allowed at all

# 2) Allow YOUR own scripts but require downloaded ones to be signed.
#    RemoteSigned is the recommended setting for a dev machine.
#    -Scope CurrentUser does NOT need Administrator rights.
Set-ExecutionPolicy RemoteSigned -Scope CurrentUser

# 3) Confirm it stuck
Get-ExecutionPolicy
# RemoteSigned      <- your scripts now run; the internet's still gated

Restricted
RemoteSigned

# 🎯 YOUR TURN — make this script survive a missing file.
# By default a non-terminating error is just printed and the script
# carries on. -ErrorAction Stop turns it into a real exception that
# try/catch can actually catch.

$path = 'C:\Reports\sales.csv'

try {
    # 1) Read the file, but force a STOP on failure so catch fires
    $data = Get-Content $path ___      # 👉 add: -ErrorAction Stop
    Write-Output "Read $($data.Count) lines."
}
catch {
    # 2) $_ is the error that was thrown — log its message
    Write-Warning "Could not read the file: $(___)"   # 👉 use $_.Exception.Message
}
finally {
    # finally ALWAYS runs — success or failure — great for cleanup
    Write-Output 'Done.'
}

# ✅ Expected output (when C:\Reports\sales.csv does NOT exist):
#    WARNING: Could not read the file: Cannot find path 'C:\Reports\sales.csv' because it does not exist.
#    Done.

WARNING: Could not read the file: Cannot find path 'C:\Reports\sales.csv' because it does not exist.
Done.

# A MODULE is a reusable package of cmdlets someone else (or you) wrote.
# Modules are how you get extra power without reinventing it.

# 1) What's already loaded in this session?
Get-Module
# (built-ins like Microsoft.PowerShell.Management appear here)

# 2) Find and INSTALL a module from the PowerShell Gallery (once per machine).
#    -Scope CurrentUser avoids needing Administrator.
Install-Module -Name PSScriptAnalyzer -Scope CurrentUser

# 3) IMPORT it to use its cmdlets in THIS session.
#    (Modern PowerShell auto-imports on first use, but be explicit in scripts.)
Import-Module PSScriptAnalyzer

# 4) See what the module gave you
Get-Command -Module PSScriptAnalyzer
# Invoke-ScriptAnalyzer, Invoke-Formatter, ...

# 5) Use it — lint a script for common mistakes
Invoke-ScriptAnalyzer -Path .\save-me.ps1

RuleName                        Severity   Line  Message
--------                        --------   ----  -------
PSAvoidUsingWriteHost           Warning       8  Avoid Write-Host; use Write-Output.
PSUseDeclaredVarsMoreThanAssign Warning      12  The variable 'temp' is assigned but never used.

# Run a script automatically on a schedule — no human, no GUI.
# A task is built from three parts: an Action, a Trigger, and Settings.
# (On Linux/macOS the equivalent is a cron entry; this is the Windows way.)

# WHAT to run: launch PowerShell and execute our backup script
$action = New-ScheduledTaskAction `
    -Execute 'pwsh.exe' `
    -Argument '-NoProfile -File C:\Scripts\backup.ps1'

# WHEN to run: every day at 02:00
$trigger = New-ScheduledTaskTrigger -Daily -At '2:00AM'

# HOW to run: catch up if the PC was asleep at 2am
$settings = New-ScheduledTaskSettingsSet -StartWhenAvailable

# Register (create) the task in Windows Task Scheduler
Register-ScheduledTask `
    -TaskName 'NightlyBackup' `
    -Action $action -Trigger $trigger -Settings $settings `
    -Description 'Backs up project files every night'

# Manage it later:
Get-ScheduledTask -TaskName 'NightlyBackup'         # check it exists
Start-ScheduledTask -TaskName 'NightlyBackup'       # run it now to test
Unregister-ScheduledTask -TaskName 'NightlyBackup' -Confirm:$false  # delete

TaskPath   TaskName        State
--------   --------        -----
\          NightlyBackup   Ready