Josh “Yoshi” VickersonWhat's the easiest way for me to script moving the last line of a text file to the Nth line? I have a whole directory full of files that need the exact same treatment.
Update: My solution in replies!
Turns out vim can do this directly in terminal:
vim +'$-0,$m0’ +'wq' FILE
Will move the last line ($-0) to the first line ($m0) and write the result (+wq).
Throw this in a loop and it did exactly what I needed:
for FILE in *.html; do vim +'$-0,$m7' +'wq' $FILE; done
^ loops through all html files in current directory, moves the last line to the 7th line.
Did I just move an HTML image to front matter on 120 blog posts at once?
Yes. Yes I did.
tkissing@josh Assuming N is the same for all files, maybe a two-step combo of sed and tail? Eg for N=6
sed -i "6i $(tail -n 1 $file)" && sed -i '$d' $file
Untested, probably totally wrong if you are on a Mac, will most certainly fail if the last line contains a $ etc
I'm also sure some professional sysadmin will cry over this "obviously bad idea"
@tkissing My solution was very similar, but using vim!
I knew enough about the content (already mostly normalized via many regex and various find/replace steps) that I knew for sure every file was the same.
Worked really well for what I needed, and a super useful thing to know how to do!
Dave MorrissNot that it adds much to your solution, but just out of interest I tried using 'ed'. I learnt the rudiments of this editor when setting up several DECstations using Ultrix in the 1990s which didn't have vim installed at that time:
$ for i in {01..10}; do echo "Line $i"; done > edit_test.dat
$ line=3; echo -e "m${line}\n,w" | ed -s edit_test.dat
This moves line 10 in the file after line 3.
Of course vim uses ed commands in command mode, so this is not all that exciting!