Learning PowerShell

Just one of the things I'm learning. https://github.com/hchiam/learning

Related repo: https://github.com/hchiam/learning-bash-scripts

Once you're in PowerShell, you can run the test.ps1 file:

cd learning-powershell
./test.ps1

For MacOS

brew cask install powershell
pwsh
exit

PowerShell command history

I personally like to use this:

Get-History -Count 1 | Format-List -Property *; # for just the previous/last command

https://www.howtogeek.com/298244/how-to-use-your-command-history-in-windows-powershell

Get-History

Get-History | Format-List -Property * # shows execution status and start/end times

Get-History | Export-Clixml -Path c:\users\name\desktop\commands.xml # saves history to a file

Clear-History

Clear # clears PowerShell window

Beep

[console]::beep(500,2000)

(1st parameter adjusts frequency, 2nd parameter adjusts duration)

Notify when build is done and show status

npm run build; [console]::beep(400,2000);

Get-History -Count 1 | Format-List -Property *; # you canNOT run this in a one-liner combined with the previous command, because I found it ends up printing history for the last one-liner that you entered, not for the combined one-liner that includes this history command

Set up custom PowerShell commands in 3 steps

1. To set up custom commands, set up a profile file in one of the profile folders: https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_profiles?view=powershell-7.3

2. Then add custom commands in that profile file: https://learn.microsoft.com/en-us/powershell/scripting/developer/module/how-to-write-a-powershell-script-module?view=powershell-7.3

3. And then restart powershell (if you have it already open). You can now run those custom commands!

Example custom commands test and hist in your $PROFILE file:

function test {
    param()
    Write-Output "test output"
}

function hist {
    Get-History -Count 5 | Format-List -Property *;
    Get-History;
}

Check if command exists

Get-Command somecustomcommand

function somecustomcommand {
    npm run clean;
    npm i;
    npm run build;
}

Next line of code continues running even if previous line had error

function exampleShowingCodeStillRunsEvenAfterErrorIfSeparateLines {
    asdfasdfasdf;
    echo "this still prints";
}

Recursively delete file type

ls -r *.js | rm

or

ls -r your\path\*.js | rm

To prompt/ask for input

Read-Host "Hit enter to continue";

Format PowerShell CLI with custom styling

https://www.youtube.com/watch?v=gOFsACMBEac

Test-Path $PROFILE
# likely prints out False

New-Item -Path $PROFILE -Type File -Force

notepad $PROFILE

function prompt {
  $path = $(Get-Location).Path
  $path = $path.ToLower() -replace '^([a-z]):', '/$1' -replace '\\', '/' # unix style path
  Write-Host ""
  Write-Host $path -ForegroundColor Green
  Write-Host "> " -NoNewLine -ForegroundColor Green
}

.$PROFILE
# and if get disabled error
Set-ExecutionPolicy RemoteSigned
# y
.$PROFILE

names of folders only immediately under ".":

Get-ChildItem -Path "." -Directory

number of folders only immediately under ".":

(Get-ChildItem -Path "." -Directory).Count

names of folders 2 levels below ".":

Get-ChildItem -Path . -Directory -Recurse | Where-Object { $_.FullName.Split('\').Count -eq ((Get-Location).Path.Split('\').Count + 2) }

number of folders 2 levels below ".":

(Get-ChildItem -Path . -Directory -Recurse | Where-Object { $_.FullName.Split('\').Count -eq ((Get-Location).Path.Split('\').Count + 2) }).Count

number of files with specific name 'example.txt' at 2 levels below ".":

(Get-ChildItem -Path . -Recurse | Where-Object { $_.FullName.Split('\').Count -eq ((Get-Location).Path.Split('\').Count + 2) -and $_.Name -eq 'example.txt' }).Count

write the names of folders 4 levels below "." to a file "U:\Downloads\out.txt":

Get-ChildItem -Path . -Directory -Recurse | Where-Object { $_.FullName.Split('\').Count -eq ((Get-Location).Path.Split('\').Count + 4) } | Out-File -FilePath "U:\Downloads\out.txt"

write to file:

# ... | Out-File -FilePath "U:\Downloads\out.txt"