[ale] Move last line of a file to first line

[Lightner, Jeff]

I wasn't aware of the tac command.  It may be all I need as I don't think the order of the other records is important in which case this should work:

tac originalfile >newfile

Thanks.





-----Original Message-----
From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of mike at trausch.us
Sent: Wednesday, March 28, 2012 11:28 AM
To: ale at ale.org
Subject: Re: [ale] Move last line of a file to first line

On 03/28/2012 11:10 AM, Lightner, Jeff wrote:
> What is the best way to move that last line of a text file to be the
> first line?

"Best" is subjective...

> Please answer the question as asked and don't suggest making the file be
> in the correct order when we receive it or changing the automated
> processing to read the last line first.  Assume those aren't options.

k...

> What I came up with was to do tail -1 >newfile and head -<number of
> lines - 1> but was thinking there ought to be a better way.

I would do something similar:

#!/bin/bash
# Put the last line of the file specified into the
# first line of the file specified.

TMP_FILE="$1".$$
tac "$1"|head -n 1 > "${TMP_FILE}"
tac "$1"|tail -n +2|tac >> "${TMP_FILE}"
mv "${TMP_FILE}" "$1"

        --- Mike

--
A man who reasons deliberately, manages it better after studying Logic
than he could before, if he is sincere about it and has common sense.
                                   --- Carveth Read, "Logic"





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