PowerShell script speed standalone vs within Visual Code - powershell

Question

I have a simple PowerShell script that writes to a file a list of recently added files.
$fpath = "\\DS1821\video\movies"
$file1 = "C:\Users\brian.w.williams\Desktop\RecentMovie.txt"
if (Test-Path $file1) {Remove-Item -Path $file1}
Get-ChildItem -Path "$fpath" -File -Recurse -Include "*.eng.srt" |
ForEach-Object {
$movie = $_.BaseName -replace ".eng",""
if ( ($_.LastWriteTime.Month -ge 7) -and ($_.LastWriteTime.Year -ge 2021) ) {
Write-Host $movie " = " $_.LastWriteTime
Write-Output $movie | Out-file $file1 -append;
}
}
The script works fine. But I noticed that the script runs much faster (a couple of minutes) when run within Visual Code (i.e. "Run without debugging"). When I run the script standalone (i.e. "Run with PowerShell") the script can take hours to complete. Why the difference? Is there anything I can do to speed it up? I have tried mapping the network folder, but that made no difference.

Answer 1

There is improvement to be made to help the code speed up.
First of all, using Write-Host and Write-Output to append to a file inside the ForEach loop is very time consuming.
Then you're using parameter -Include on Get-ChildItem, where you really want to use -Filter. A Filter is MUCH faster than Include, because the latter will only filter the filenames afterwards. -Filter however can only work on one single filename pattern, but this is exactly what you are doing here.
The if(..) can also be improved to have it compare only one value (a datetime) instead of two separate properties from LastWriteTime.
Try:
$sourcePath = '\\DS1821\video\movies'
# set a variable to an output file on your desktop
$outputFile = Join-Path -Path ([Environment]::GetFolderPath("Desktop")) -ChildPath 'RecentMovies.txt'
# set the reference date in a variable for faster comparison later
$refdate = (Get-Date -Year 2021 -Month 7 -Day 1).Date
# get the files, filter on the name ending in '*.eng.srt'
# filter more with Where-Object so you'll get only files newer than or equal to the reference date
# output objects with one calculated property ('MovieName') and the LastWriteTime
$movies = Get-ChildItem -Path $sourcePath -File -Recurse -Filter '*.eng.srt' |
Where-Object { $_.LastWriteTime -ge $refdate } |
Select-Object #{Name = 'MovieName'; Expression = {$_.BaseName -replace '\.eng\.srt$', '.srt'}},
LastWriteTime
# now output what you have collected to file.
# Set-Content creates a new file or overwrites an existing file
$movies.MovieName | Set-Content -Path $outputFile
# and to screen
$movies | ForEach-Object { Write-Host ('{0} = {1}' -f $_.MovieName, $_.LastWriteTime.ToString()) }
# or to Out-GridView if you prefer
$movies | Out-GridView -Title 'My Movies'
1. I've changed some variable names to make the code better readable
2. Since -replace uses regex, you have to escape the dots with a backslash. The regex also anchors the string to the end of the BaseName with the dollar sign ($) at the end