Search multiple folders and muiltiple files and combine to single file

Question

 I want to search multiple folders for muliple files and combine to single file name. The files I'm searching have same format, but where named
differently in each of there processes. Now I want to combine based upon -SearchFor .. I'm having a problem with -Filter $SearchFor
Code:
Function Search-Files{
Param([String[]]$Locations,[String[]]$SearchFor, $AppendTo)
Begin
If(-Not (Test-Path $AppendTo)){New-Item $AppendTo -ItemType File -Force}
Process
ForEach($Location in $Locations)
$Files = Get-ChildItem -Path $Location -Filter $SearchFor -Recurse
ForEach($File in $Files)
Get-Content -Path $FIles.FullName | Out-File $AppendTo -Append
End{}
Search-Files -Locations "\\servera\public\t1\usa\saleshist\","\\serverb\public\t2\usa\saleshist\",-SearchFor "dodetail-cm.txt","somstr.txt",-AppendTo "\\virt1\Saleshist_data_load_files\saleshdr.load.csv"

Answer 1

I think you might want to use -Include instead of -Filter.  Your -Include parameter accepts wildcards, i.e. *.docx or *somstr.txt
Your command to actually append the content should be:
Get-Content -Path $File.FullName | Out-File $AppendTo -Append
You had $Files.FullName which might behave unexpectedly, if at all.
Your actual command has several issues.
Search-Files -Locations "\\servera\public\t1\usa\saleshist\","\\serverb\public\t2\usa\saleshist\" -SearchFor "dodetail-cm.txt","somstr.txt" -AppendTo "\\virt1\Saleshist_data_load_files\saleshdr.load.csv"
You had commas following the lists of locations and searchfor terms, did that even work? Without seeing your source files or your target file I can only advise you so much, but ideally you would import-csv and export-csv.  Depending on the contents,
you may be able to get away with get-content and out-file though.
I hope this post has helped!