Vista - Looking to delete last 3 lines with powershell

I want to delete the last three lines of a file using powershell, there
doesnt seem to be an easy answer????

On Oct 29, 4:16*pm, DUHAAS <DUH...@xxxxxx> wrote:You are almost going to need to stick something like this in your
pipeline

% -begin {$a,$b,$c=$null
}-process {$a=$b;$b=$c;$c=$_;if ($a){$a}}

This doesn't start emitting objects until you've read 3.
Since the pipeline stops with the contents of $b, $c and $_
having never been emitted they dissappear.

You could abstract the concept to use a FIFO Stack rather than hard
coding the size if you need more flexibility.

Hi DUHAAS,

This will read a file content (assuming it has more then 3 lines), and output
every line except for the last three:

$content = get-content file.txt
$content[0..($content.length-4)]


---
Shay Levy
Windows PowerShell MVP
http://blogs.microsoft.co.il/blogs/ScriptFanatic
PowerShell Toolbar: http://tinyurl.com/PSToolbar



D> I want to delete the last three lines of a file using powershell,
D> there doesnt seem to be an easy answer????
D>

Hi,
Just one way, I'm sure there will be more correct, faster, beautiful
ways to do it.

Anyway, in this one-liner hh.txt is your starting file and hh2 is the
same but less
the last three lines. Nothing stopping you overwriting the start file,
if thats what you want.

Seems to work ok on several test text files I played around with.

$a = gc hh.txt; $c = $($a.Count -1) ; $c..$($c -2) | % {$a[$_] = Out-
Null } ; sc -path hh2.txt -va $a

Hope it helps,
Stuart











On 29 Oct, 21:16, DUHAAS <DUH...@xxxxxx> wrote:

On Oct 29, 5:02*pm, RickB <rbiel...@xxxxxx> wrote:I noticed the other solutions assume the data source is small enough
to be loaded into memory. That's probably true in many cases. I
typically deal with files in the 100's of MB so I'm alwasy thinking
BIG. This tosses the last X records in a stream.

$X = 3

<data src>|% -begin{$q = new-object system.collections.queue
}-process{$q.enqueue($_);if ($q.count -gt $X){$q.dequeue()}|
<data dest>