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Delete first 10 lines of a file

Last Post 26 Jun 2008 11:00 AM by BauerShell. 9 Replies.

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duhaas

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20 Jun 2008 09:56 PM
trying to find a script that will delete first 10 lines from a file. thanks in advance

marco.shaw User is Offline

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21 Jun 2008 04:01 PM
There's nothing that can actually delete lines from an existing file, that I'm aware of. You'll have to do something like this: get-content test.txt\|select-object -last ((get-content test.txt).count - 9)\|out-file test2.txt What you're doing is creating a new file. You could then overwrite the original with the new. Marco

Marco Microsoft MVP - Windows PowerShell: http://www.microsoft.com/mvp PowerGadgets MVP: http://www.powergadgets.com/mvp *Blog: http://marcoshaw.blogspot.com

duhaas

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21 Jun 2008 04:31 PM
Thanks for the help, in doing this: gc F:\MonthlyINV053108.csv \| Select-Object -first ((gc F:\MonthlyINV053108.csv).count -11)\|out-file test.txt it doesnt appear to be removing the first 11 lines, but it is removing the last 11??

Karl

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21 Jun 2008 07:54 PM
Here is something that works.. and is also pipeline friendly, and more preformant because you arne't reading the same file in twice. get-Content c:\test.csv \| foreach -begin {$count = 0 } -process{$count++;if ($count -gt 10 ) {$_} } \| out-File c:\test2.csv however this ability to skip so many items of anything in a pipeline is useful in general so we can distill this logic down to a function that can help us. function skip([int]$amount) { begin {$count = 0 } process {$count++;if ($count -gt $amount ) {$_} } } and then with this function our one liner is much cleaner get-Content c:\test.csv \| skip 10 \| out-File c:\test2.csv

jsnover

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21 Jun 2008 10:14 PM
In PS V2, we have Select -SKIP cat test.csv \|select -skip 10 jps

duhaas

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23 Jun 2008 05:26 PM
Thanks everyone for the wonderful advice. Being new to powershell its really nice to have a community like this to bounce ideas off of

duhaas

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23 Jun 2008 05:27 PM
I do still have one question, and its not a huge deal, but the original .txt file I bring in is 9MB in size, and the output that it spits out is 17.5MB in size, any reason for the increase in size if I'm just removing the first 7 lines.

marco.shaw User is Offline

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23 Jun 2008 05:31 PM
Posted By duhaas on 06/21/2008 8:31 AM Thanks for the help, in doing this: gc F:\MonthlyINV053108.csv \| Select-Object -first ((gc F:\MonthlyINV053108.csv).count -11)\|out-file test.txt it doesnt appear to be removing the first 11 lines, but it is removing the last 11?? Note: You used "-first", and I had used "-last".

Marco Microsoft MVP - Windows PowerShell: http://www.microsoft.com/mvp PowerGadgets MVP: http://www.powergadgets.com/mvp *Blog: http://marcoshaw.blogspot.com

Karl

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23 Jun 2008 05:35 PM
ahh the default format for out-file is UNICODE, which will explain the filesize increase you can force ascii with out-file -encoding ASCII /Karl

BauerShell User is Offline

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26 Jun 2008 11:00 AM
another smooth way would be to directly index into the content (gc "F:\MonthlyINV053108.csv ")[10..((gc "F:\MonthlyINV053108.csv ").length)] \| Out-File -encoding ASCII test.txt

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