How to use sed to remove the last n lines of a file

Question

I want to remove some n lines from the end of a file. Can this be done using sed?

For example, to remove lines from 2 to 4, I can use

$ sed          


        

Answer 1

sed -n ':pre
1,4 {N;b pre
    }
:cycle
$!{P;N;D;b cycle
  }' YourFile

posix version

Answer 2

For deleting the last N lines of a file, you can use the same concept of

$ sed '2,4d' file

You can use a combo with tail command to reverse the file: if N is 5

$ tail -r file | sed '1,5d' file | tail -r > file

And this way runs also where head -n -5 file command doesn't run (like on a mac!).

Answer 3

I don't know about sed, but it can be done with head:

head -n -2 myfile.txt

Answer 4

Try the following command:

n = line number
tail -r file_name | sed '1,nd' | tail -r

Answer 5

I prefer this solution;

head -$(gcalctool -s $(cat file | wc -l)-N) file

where N is the number of lines to remove.

Answer 6

It can be done in 3 steps:

a) Count the number of lines in the file you want to edit:

 n=`cat myfile |wc -l`

b) Subtract from that number the number of lines to delete:

 x=$((n-3))

c) Tell sed to delete from that line number ($x) to the end:

 sed "$x,\$d" myfile