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

In docker, this worked for me:

head --lines=-N file_path >> file_path

Answer 2

This might work for you (GNU sed):

sed ':a;$!N;1,4ba;P;$d;D' file

Answer 3

This will remove the last 12 lines

sed -n -e :a -e '1,10!{P;N;D;};N;ba'

Answer 4

You could use head for this.

Use

$ head --lines=-N file > new_file

where N is the number of lines you want to remove from the file.

The contents of the original file minus the last N lines are now in new_file

Answer 5

You can get the total count of lines with wc -l <file> and use

head -n <total lines - lines to remove> <file>

Answer 6

With the answers here you'd have already learnt that sed is not the best tool for this application.

However I do think there is a way to do this in using sed; the idea is to append N lines to hold space untill you are able read without hitting EOF. When EOF is hit, print the contents of hold space and quit.

sed -e '$!{N;N;N;N;N;N;H;}' -e x

The sed command above will omit last 5 lines.