How to search for multiple terms/regex to be contained in the file, but not necessary the same line

Question

How do I use Powershell to find text files containing all search terms/patterns, but not necessarily in the same line? Chaining Select-String only finds the terms contained in the same line.

Select-String -Path .\*.md -Pattern 'termA' | Select-String -Pattern 'termB' -List | Select-Object Filename

only finds files containing the terms in the same line. I want to find all files containing all terms/patterns I am looking for (should be whatever number of terms/patterns), anywhere in the file.

Answer 1

Test each file one at a time, but repeat Select-String once per term - you can then discard the file as soon as any one term is not found:

$searchTerms = @(
  'termA'
  'termB'
)

Get-ChildItem -Path . -Filter *.md |Where-Object {
  foreach($term in $searchTerms) {
    $firstMatch = $_ |Select-String -Pattern $term |Select-Object -First 1
    # we're not interested if any of the terms are missing
    if (-not $firstMatch) { return $false }
  }
  # we've reached the end, all terms must have been found
  return $true
}