Powershell add text to start, end of output file - powershell

Question

I have a folder containing multiple text files that I am combining into one file. On that output file I need to add a string to the top and the bottom of the file. I have tried using insert and I keep getting an error. The file is contained in the $Output variable
My code so far:
if(!(Test-Path -Path $PathDump)) {
# create the folder if it does not yet exist
New-Item -ItemType Directory $PathDump
}
# move all *.txt items from 'C:\RemoveFirst\txt' to 'C:\RemoveFirst\DumpARoo'
# EXCEPT the output file itself
$Path = (Get-ChildItem -Path $Path -Filter '*.txt' -File).FullName | Where-Object { $_ -ne $Output}
Move-Item -Path $Path -Destination $PathDump # move (not copy) files into new directory to concat
Get-ChildItem -Path $PathDump -Filter '*.txt' -File | ForEach-Object {
'' # Output an empty line at SOF
'---------------------------------------------------------------'
$_ | Get-Content | Select-Object -Skip 1 | Select-Object -SkipLast 1
'---------------------------------------------------------------'
'' # Output an empty line at EOF
} | Add-Content -Path $OutPut

Answer 1

The story continues ;)
Try this:
$Path = 'C:\RemoveFirst\*.txt'
$PathDump = 'C:\RemoveFirst\DumpARoo'
$Output = 'C:\RemoveFirst\TestingFile.txt'
if(!(Test-Path -Path $PathDump)) {
# create the folder if it does not yet exist
New-Item -ItemType Directory $PathDump
}
# move all *.txt items from 'C:\RemoveFirst\txt' to 'C:\RemoveFirst\DumpARoo'
# EXCEPT the output file itself
$Path = (Get-ChildItem -Path $Path -Filter '*.txt' -File).FullName | Where-Object { $_ -ne $Output}
Move-Item -Path $Path -Destination $PathDump # move (not copy) files into new directory to concat
# Output 'SOF'
"SOF" | Add-Content -Path $OutPut
Get-ChildItem -Path $PathDump -Filter '*.txt' -File | ForEach-Object {
# output the content of the current file
$_ | Get-Content | Select-Object -Skip 1 | Select-Object -SkipLast 1 | Add-Content -Path $OutPut
}
# Output 'EOF'
"EOF" | Add-Content -Path $OutPut