How to insert a line in a file before the last line?

Question

linux

You need to insert a line in the file before its last line.
How it is better to implement it?

Answer 1

There is a multi-word option

#!/bin/bash

NEED_STR='penultimate line'

FILE='need_file_path'

LAST=$(tail -1 $FILE)
sed -i '$ d' $FILE
echo "$NEED_STR" >> $FILE
echo "$LAST" >> $FILE

It could probably be shorter, but I can't think of it.

Answer 2

AWK script, takes the string to be inserted as an argument, redirect I / O to the necessary files:

BEGIN {
   s = "\n"
}

{
    if ( s != "\n" ) print s ;
    s = $0 ;
}

END {
    print ARGV [ 1 ] ;
    print s ;
}

Answer 3

sed -i '$iстрока' /tmp/file.txt