.. having advertised Powershell upthread, I found it fell on its face at the last hurdle. I wanted to grep a file, and discovered that the default output formatters will either truncate or wrap lines, even when directed into a file. This is wrong and destroys data. I ended up with

Select-String " 23:56.00" -Path .\input.txt | ForEach-Object { Write-Output $_.Line } | Out-File outpu.txt