PowerShell Basics examples

PowerShellBuildingBlocks.ps1

#PowerShell Building Blocks

#Single-line comments begin with a pound sign.

<#  Multi-line comments can span between angle brackets and pound signs.
    Just like this.
The syntax highlighter in PowerShell ISE colors comments green so they're easy to see. #>

#Output
#Output to the monitor
Write-Host "Hello World"

#More generic output, better for file output
Write-Output "Hello World"

#Clear the monitor of previous output
Clear-Host

#Input
# Prompt with a question, input the answer, clear the screen, and display it back to the user.
Write-Output "What is your favorite color?"
$color = Read-Host
Clear-Host
Write-Host "Your favorite color is" $color"." -ForegroundColor $color

#Variables
#Save content to a variable to work with later.
$total = 2+2
Write-Host $total

#Auto-increment or decrement a variable
$total = 0
$total++
Write-Host $total
$total++
Write-Host $total
$total--
Write-Host $total
$total--
Write-Host $total

#You can also read system environment variables like the computer name
$computername = $env:COMPUTERNAME
Write-Host $computername
#... or PowerShell version
$psversion = $psversiontable.PSVersion
Write-Host $psversion

#Piping
#Get-Process returns the active processes (like TaskMgr)
Get-Process 
#Piping the results to select-object allows us to filter just the columns we want.
Get-Process | Select-Object ProcessName

#Format output
#Format the output to be a table by piping the results to format-table
Get-Process | Format-Table
#Format the output to be a list by piping the results to format-list
Get-Process | Format-List

#These can be shortened to aliases, ft for table and fl for list
Get-Process | ft
Get-Process | fl

#Create a folder
New-Item C:\scripting -type Directory

#Write out to a file
$total = 1+1
Write-Output $total | Out-file C:\scripting\demo.txt

#Write out to a file without overwriting the contents, instead adding to it, or appending.
$total = 1+1+1
Write-Output $total | Out-file C:\scripting\demo.txt -Append

#Work with files
#Conditional, Does file exist?
If (Test-Path "C:\Scripting\demo.txt"){
  #Demo file exists, read file
  $read = Get-Content "C:\Scripting\demo.txt"
  #Create new file
  New-Item -path C:\scripting -name demo2.txt -type "file" -value "File existed"
} else {
    #Demo file does not exist, create file
    Write-Output "Creating file" | Out-file C:\scripting\demo.txt
    #or
    New-Item -path C:\scripting -name demo2.txt -type "file" -value "File did not exist"
}

#Creating a new folder
New-Item C:\scripting2 -type Directory

#Moving file from scripting folder to scripting2
Move-Item -path C:\scripting\demo.txt -destination C:\scripting2\demo.txt

#Copying file from scripting folder to scripting2
Copy-Item -path C:\scripting\demo2.txt -destination C:\scripting2\demo2.txt

#Delete files and directories
remove-item -path C:\Scripting\demo2.txt
remove-item -path C:\Scripting
#or delete folder and subfolder/files
remove-item -path C:\scripting2 -Recurse

#Ping
Test-Connection server.fqdn
if (Test-Connection server.fqdn -quiet) {
    #Server is available to ping
} else {
    #Server is unavailable to ping
}

#Loops until variable is no longer less than 5
$total = 0
Do {
    Write-Host $total -ForegroundColor "Magenta"
    $total++
} While ($total -lt '5')

#Loops until variable is greater than 4
$total = 0
Do {
    Write-Host $total -ForegroundColor "Yellow"
    $total++
} Until ($total -gt '4')


#Functions
function calculateTip {
    $totalwtip = $args[0] * 1.15
    Write-Output "Total of $args with 15% tip is $totalwtip"
}
calculateTip 25
calculateTip 50

exit