# encoding: ascii
# api: powershell
# title: Get-Tail.ps1
# version: 0.1
# type: script
# license: CC0
# function: Get-Tail
# x-poshcode-id: 2618
# x-archived: 2011-04-20T17:29:46
# x-published: 2011-04-18T23:56:00
#
# Name: Get-Tail.ps1
# Author: William Stacey
# Created: 02/22/2007
# Description: Gets the last N lines of a file. Does scan from end-of-file so works on large files. Also has a loop flag that prompts for refresh.
function Get-Tail([string]$path = $(throw "Path name must be specified."), [int]$count = 10, [bool]$loop = $false)
{
if ( $count -lt 1 ) {$(throw "Count must be greater than 1.")}
function get-last
{
$lineCount = 0
$reader = new-object -typename System.IO.StreamReader -argumentlist $path, $true
[long]$pos = $reader.BaseStream.Length - 1
while($pos -gt 0)
{
$reader.BaseStream.Position = $pos
if ($reader.BaseStream.ReadByte() -eq 10)
{
if($pos -eq $reader.BaseStream.Length - 1)
{
$count++
}
$lineCount++
if ($lineCount -ge $count) { break }
}
$pos--
}
if ($lineCount -lt $count)
{
$reader.BaseStream.Position = 0
}
while($line = $reader.ReadLine())
{
$lines += ,$line
}
$reader.Close()
$lines
}
while(1)
{
get-last
if ( ! $loop ) { break }
$in = read-host -prompt "Hit [Enter] to tail again or Ctrl-C to exit"
}
}