[DJ Mogarych]

Powershell

Код:

$n = 6

# первые
(gc "C:\temp\Untitled 1.txt") -replace "^.{$n}" > "C:\temp\Untitled 2.txt"

# последние
(gc "C:\temp\Untitled 1.txt") -replace ".{$n}$" > "C:\temp\Untitled 2.txt"