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

Fri Mar 30 08:42:57 EDT 2012

On 03/29/2012 12:29 AM, Richard Bronosky wrote:
> Sadly, I only know "of" ed. But, thanks to you, Ed, I'm now interested
> in using ed in my daily workflow. I like this particular use case.
> I've added it to my gist.
> https://gist.github.com/2228256#file_flop2.sh (I<3 heredoc syntax)

I used to used ed all the time when I first starting using UNIX.  You 
can incorporate Ed's ed commands in a here document, stick it in a 
script and you have all you need:

cat <<END|ed data
m0
w
q
END

>
> On Wed, Mar 28, 2012 at 9:57 PM, Ed Cashin<ecashin at noserose.net>  wrote:
>> Thanks for mentioning the non-stream editor!  They made sed for streams,
>> because ed is for files.  It is at times like this when I sincerely regret
>> the way distros are beginning to omit ed for the first time in decades.
>>
>> There's an ed move command called "m".  Move this line to that line.  The
>> one liner below does the same thing as this interactive session
>>
>> $m0
>> w
>> q
>>
>> ecashin at reynolds:~$ head /etc/passwd | nl>  ~/tmp/a
>> ecashin at reynolds:~$ cp ~/tmp/a ~/tmp/b
>> ecashin at reynolds:~$ printf '$m0\nw\nq\n' | ed ~/tmp/b
>> 414
>> 414
>> ecashin at reynolds:~$ diff -u ~/tmp/a ~/tmp/b
>> --- /home/ecashin/tmp/a 2012-03-28 21:40:25.000000000 -0400
>> +++ /home/ecashin/tmp/b 2012-03-28 21:41:44.000000000 -0400
>> @@ -1,3 +1,4 @@
>> +    10 news:x:9:9:news:/var/spool/news:/bin/sh
>>        1 root:x:0:0:root:/root:/bin/bash
>>        2 daemon:x:1:1:daemon:/usr/sbin:/bin/sh
>>        3 bin:x:2:2:bin:/bin:/bin/sh
>> @@ -7,4 +8,3 @@
>>        7 man:x:6:12:man:/var/cache/man:/bin/sh
>>        8 lp:x:7:7:lp:/var/spool/lpd:/bin/sh
>>        9 mail:x:8:8:mail:/var/mail:/bin/sh
>> -    10 news:x:9:9:news:/var/spool/news:/bin/sh
>> ecashin at reynolds:~$
>>
>> On Wed, Mar 28, 2012 at 12:41 PM, Richard Bronosky<Richard at bronosky.com>
>> wrote:
>>>
>>> Be careful doing this with large files. You are storing the whole file
>>> in memory.
>>>
>>> I would do this in 2 passes.
>>>
>>> # First get the last line into a new file. (assuming the file in
>>> question is passed in as the first argument)
>>> tail -n1 $1>  $1.mod
>>> # Second add the rest of the file, less the last line.
>>> sed '$d' $1>>  $1.mod
>>>
>>> This is working with streams. It requires an additional $filesize of
>>> disk space, but it does not require $filesize of RAM.
>>>
>>> If you want to be really efficient, use ed. ;-)
>>> # This will trim the last line of the file in place, but I'm not
>>> taking the time to figure out how to add it to the beginning.
>>> ed "$1"<<  EOF
>>> $
>>> d
>>> w
>>> EOF
>>>
>>> On Mar 28, 2012 11:19 AM, "Lightner, Jeff"<JLightner at water.com>  wrote:
>>>>
>>>> I found this works:
>>>>
>>>> awk '{a[NR]=$0} END {print a[NR]; for (i=1;i<NR;i++) print a[i]}'
>>>> originalfile>newfile
>>>>
>>>>
>>>>
>>>> Where you replace originalfile and newfile with real file names.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ________________________________
>>>>
>>>> From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of
>>>> Lightner, Jeff
>>>> Sent: Wednesday, March 28, 2012 11:10 AM
>>>> To: Atlanta Linux Enthusiasts
>>>> Subject: [ale] Move last line of a file to first line
>>>>
>>>>
>>>>
>>>> We have variable length text files being received in which the “header”
>>>> line we use in automated processing is the last line of the file rather than
>>>> the first line.
>>>>
>>>>
>>>>
>>>> What is the best way to move that last line of a text file to be the
>>>> first line?
>>>>
>>>>
>>>>
>>>> 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.
>>>>
>>>>
>>>>
>>>> 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 see sed can deal with last line, first line and insertion but the
>>>> examples I’m finding address either/or not moving last line to first line.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Athena®, Created for the Cause™
>>>>
>>>> Making a Difference in the Fight Against Breast Cancer
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> How and Why I Should Support Bottled Water!
>>>> Do not relinquish your right to choose bottled water as a healthy
>>>> alternative to beverages that contain sugar, calories, etc. Your support of
>>>> bottled water will make a difference! Your signatures count! Go to
>>>> http://www.bottledwatermatters.org/luv-bottledwater-iframe/dswaters and sign
>>>> a petition to support your right to always choose bottled water. Help fight
>>>> federal and state issues, such as bottle deposits (or taxes) and
>>>> organizations that want to ban the sale of bottled water. Support community
>>>> curbside recycling programs. Support bottled water as a healthy way to
>>>> maintain proper hydration. Our goal is 50,000 signatures. Share this
>>>> petition with your friends and family today!
>>>>
>>>>
>>>>
>>>> ---------------------------------
>>>> CONFIDENTIALITY NOTICE: This e-mail may contain privileged or
>>>> confidential information and is for the sole use of the intended
>>>> recipient(s). If you are not the intended recipient, any disclosure,
>>>> copying, distribution, or use of the contents of this information is
>>>> prohibited and may be unlawful. If you have received this electronic
>>>> transmission in error, please reply immediately to the sender that you have
>>>> received the message in error, and delete it. Thank you.
>>>> ----------------------------------
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Ale mailing list
>>>> Ale at ale.org
>>>> http://mail.ale.org/mailman/listinfo/ale
>>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>>> http://mail.ale.org/mailman/listinfo
>>>>
>>>
>>> _______________________________________________
>>> Ale mailing list
>>> Ale at ale.org
>>> http://mail.ale.org/mailman/listinfo/ale
>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>> http://mail.ale.org/mailman/listinfo
>>
>>
>>
>>
>> --
>>    Ed Cashin<ecashin at noserose.net>
>>    http://noserose.net/e/
>>    http://www.coraid.com/
>>
>> _______________________________________________
>> Ale mailing list
>> Ale at ale.org
>> http://mail.ale.org/mailman/listinfo/ale
>> See JOBS, ANNOUNCE and SCHOOLS lists at
>> http://mail.ale.org/mailman/listinfo
>>
>
>
>

-- 
Until later, Geoffrey

"I predict future happiness for America if they can prevent
the government from wasting the labors of the people under
the pretense of taking care of them."
- Thomas Jefferson