Powershell: I'm unable to delete a line from a text file - powershell

Question

Here's a method for deleting a line that I thought would work
#earlier in the script
$inFile = Get-Content -Path ".\input.txt"
# ...Later... #
$inFile = Get-Content -path ".\input.txt" | where-object {$_ -notmatch $line}
set-content -path ".\input.txt" -Value $inFile
The problem is that the -notmatch parameter doesn't seem to work. The Get-Content cmdlet just copies all the content from input.txt, including $line. I've also tried changing the code to clear $inFile completley and create a temporary holder, but no dice.
Clear-Variable -name "inFile"
$holder = Get-Content -path ".\input.txt" | where-object {$_ -notmatch $line}
set-content -path ".\input.txt" -Value $holder
$inFile = Get-Content -path ".\input.txt"
Am I using -notmatch incorrectly? Here's the full text script for context.
Write-Host "Starting"
[bool] $keepRunning = 1
[bool] $everFound = 0
[bool] $searchComplete = 0
:main while($keepRunning)
{
$inFile = Get-Content -path ".\input.txt"
$completed = Get-Content -Path ".\output.txt"
$line = $inFile[0]
$holder
if($inFile.count -eq 1)
{
$line = $inFile
}
# create condition to check if $line matches any line in completed.txt
# if it does, skip this line and move on to the next line
:search while($everFound -eq 0 -and $searchComplete -eq 0)
{
#Write-Host "Outer loop"
foreach($url in $completed)
{
#Write-Host $line
#write-host $url
if ($line -eq $url)
{
Write-Host "`nThis file was already downloaded --Skipping to the next line"
$inFile = Get-Content -path ".\input.txt" | where-object {$_ -notmatch $line}
set-content -path ".\input.txt" -Value $inFile
$inFile = Get-Content -path ".\input.txt"
$line = $inFile[0]
$everFound = 1
break
}
}
if ($everFound -eq 1)
{
break
}
$searchComplete = 1
Write-Host "Search Complete`n"
}
Write-Host "Before the download--------"
Write-Host $everFound
Write-Host $searchComplete
if ($everFound -eq 0 -and $searchComplete -eq 1)
{
#download the files
$downloadCommand = "youtube-dl.exe --verbose --cookies .\cookies.txt `"$line`""
get-date
invoke-Expression $downloadCommand
#delete the url
add-content -Path ".\output.txt" -Value $line
$inFile = Get-Content -path ".\input.txt" | where-object {$_ -notmatch $line}
set-content -path ".\input.txt" -Value $inFile
write-host "`n"
get-date
Write-Host "Sleeping for 45mins"
#start-sleep -s 2700
}
$everFound = 0
$searchComplete = 0
Write-Host "-------------After the download!!"
Write-Host $everFound
Write-Host $searchComplete
# check if the file is empty. If it is, set the keepRunning flag to false and exit the main while loop
if($Null -eq $inFile)
{
$keepRunning = 0
}
}
Write-Host "Done"
Read-Host "Press the Enter Key to Exit"
EDIT:
$inFile contains a list of youtube URLs on each line. $line is assigned the value of the first line of $inFile
$line = $inFile[0]
Here is a youtube URL: https://www.youtube.com/watch?v=sB5zlHMsM7k
I also added some statements to output the values of $line right before the file. Someone please point me to the right direction.

Answer 1

Am I using -notmatch incorrectly?
You're using it incorrectly, if $line contains a substring to search for literally (as-is, verbatim) in the input file's lines, and that substring happens to contain regex metacharacters, such as . and $.
To use -match / -notmatch for literal substring matching, you must escape the substring:
$_ -notmatch [regex]::Escape($line)
If you want to match lines only in full, you must anchor the regex:
$_ -notmatch ('^' + [regex]::Escape($line) + '$')
Note that PowerShell has no operator for literal substring matching.
However, the System.String ([string]) type has a .Contains() method for literal substring matching, but not that, unlike PowerShell's operators, it is case-sensitive by default (there are overloads for case-insensitive matching, but only in PowerShell (Core) 7+):
-not $_.Contains($line) # case-sensitive, literal substring matching
# PS 7+ only: case-INsensitive, literal substring matching
-not $_.Contains($line, 'CurrentCultureIgnoreCase')
For full-line matching:
-not ($_.Length -eq $line.Length -and $_.Contains($line))
or:
-not $_.Equals($line, 'CurrentCultureIgnoreCase')
The advantage of using .Contains() is that it performs better than -match, though the latter offers much more flexibility.