I found a post about users that wanted to use grep in PowerShell. For example,
PS> Get-Content file_to_grep | Select-String \"the_thing_to_grep_for\" <
PS> Get-Content file_to_grep | Select-String \"the_thing_to_grep_for\"
Select-String has the NotMatch parameter.
NotMatch
get-content file_to_grep | select-string -notmatch "the_thing_to_grep_for"