PowerShell CheatSheet – Maths!

PowerShell loves maths!
By using System.Math .NET Framework class, PowerShell is a great calculator.
Here are common examples of System.Math functions

1. Returning the absolute value of a Decimal number

[int]$x=-19.69
[System.Math]::Abs($x)

2. Returning the smallest integral value that is greater than or equal to the specified decimal number

[int]$x=-19.69
[System.Math]::Ceiling($x)

3. Returning the largest integer less than or equal to the specified decimal number

[int]$x=-19.69
[System.Math]::Floor($x)

4. Returning the larger of two decimal numbers

[int]$x=9
[int]$y=42
[System.Math]::Max($x,$y)

5. Returning the smaller of two decimal numbers

[int]$x=9
[int]$y=42
[System.Math]::Min($x,$y)

6. Returning a specified number raised to the specified power

[int]$x=9
[System.Math]::Pow($x,2)

7. Returning a decimal value to the nearest integral value

[int]$x=9.9548
[System.Math]::Round($x,2)

8. Returning the square root of a specified number

[int]$x=81
[System.Math]::Sqrt($x)

9. Calculating the integral part of a specified decimal number

[int]$x=56648.4665
[System.Math]::Truncate($x)

10. Calculating the area of a circle (or anything Pi’s related…)

[decimal]$Pi=[System.Math]::Pi
[int]$radius=10
$area=([System.Math]::Pow($radius,2)) * $Pi

Of course, for sysadmins, the most used function will be to convert values from bytes to Kb, Mb, Gb, etc. PowerShell knows about it:

PS Fab:\> 1KB
1024
PS Fab:\> 1MB
1048576
PS Fab:\> 1GB
1073741824
PS Fab:\> 1TB
1099511627776
PS Fab:\> 1PB
1125899906842624

It’s probably in server inventory, dealing with disk spaces, that you will use those most:

$disk=Get-WmiObject Win32_LogicalDisk -Filter "DeviceID='C:'" | Select-Object $_.Size
$By=($disk.Size)
Write-Host "Disk C total capacity (in bytes) => $By bytes"
$Gb=[System.Math]::Round(($disk.Size)/1GB,2)
Write-Host "Disk C total capacity (converted in Gb) => $Gb Gb"

Finally, since PowerShell is able do mathematical operations, we can obviously use the main operators on numbers, but on strings too: