| filter GetLuma { | |
| $colorString = $_ | |
| # Convert the background color to a uint32 | |
| $rgb = ($colorString -replace "#", "0x" -replace ';') -as [UInt32] | |
| # then make it into a percentage red, green, and blue. | |
| $r, $g, $b = ([float][byte](($rgb -band 0xff0000) -shr 16)/255), | |
| ([float][byte](($rgb -band 0x00ff00) -shr 8)/255), | |
| ([float][byte]($rgb -band 0x0000ff)/255) | |
| # Calculate the luma of the background color |
| # A function without a [CmdletBinding] attribute or [Parameter] attributes is freeform. | |
| # Let's declare a little function that just outputs the name and arguments | |
| function I { | |
| param() | |
| @($MyInvocation.InvocationName) + $args | |
| } | |
| # We can use Register-ArgumentCompleter to register the completer for a named command. | |
| # This simple completer will show any matching history items | |
| Register-ArgumentCompleter -CommandName I -ScriptBlock { |
| <# | |
| .Synopsis | |
| Not On a Friday. | |
| .Description | |
| Gist a little bit of friendly advice about the wisdom of shipping software on a Friday. | |
| .Notes | |
| Yes, this runs. | |
| #> | |
| [ValidateScript({ | |
| if ([DateTime]::Now.DayOfWeek -eq 'Friday') { |
| # When run within a container, this will output the directories that are mounted as read/write. | |
| (Select-String "\S+\s(?<p>\S+).+rw,.+symlinkroot=/mnt/host" "/proc/mounts").Matches.Groups | | |
| Where-Object Name -eq p | | |
| Get-Item -path { $_.Value } | |
| # Hope This Helps! / Have Fun! |
PowerShell, as a language, is very self-discoverable.
When you Get-Command, you get a rich object about a command.
This can have a lot of metadata.
You can and should also use inline help (like this script does).
Sometimes, I want more metadata than the command or parameter can actually provide.