Joining lines in reverse. append line 1 to line 2.

Shell Programming and Scripting
1

Hi I have used many times the various methods to append two lines together in a file.

This time I want to append the 1st line to the second and repeat for the complete file.... an example

This is the file

owns the big brown dog
joe
owns the small black dog
jim

What I want is

joe owns the big brown dog
jim owns the small black dog

Thanks. Dave

2 
#  awk '{a=$0;getline;print  $0,a}' file
joe owns the big brown dog
jim owns the small black dog
3

Thanks for your help. That is exactly what I wanted.

Can you explain what happens please.

Thanks Tytalus

4

Using sed

$ sed -n 'N; s/\(^.*\)\n\(.*$\)/\2 \1/p' file
joe owns the big brown dog
jim owns the small black dog
$
5

Just for fun, pure shell solution:

i=0
while read line
    do if [ $(($i%2)) == 1 ]; then
        echo "$line $lastline"
    else
        lastline=$line
    fi
    let i=$i+1
done
6

Or:

perl -00 -pe's/(.*\n)(.*)\n/$2 $1/g' filename

Or:

while IFS= read -r y;IFS= read -r x;do 
  printf "%s\n" "$x $y"
done<filename
7 
perl -ne 'if($.%2==1){$t=$_;} if($.%2==0){$_=~tr/\n//d;print $_," ";print $t; $t="";}' file
8 
perl -ne 'if($.%2){$t=$_;} if(!$.%2){chomp;print "$_ $t";}' <file

Shortened that a bit for you.