Linux split a column into two different columns in a same CSV file [closed]

Answer 1

perl -lne 'if(/,,/){$.=0}$a{$.}=$a{$.}." ".$_ if($.!=0);END{foreach (sort keys %a){print $a{$_}}}'

Tested below:

> cat temp
11
22
13
,,
aa
bb
cc
,,
ww
kk
ll
,,
> perl -lne 'if(/,,/){$.=0}$a{$.}=$a{$.}." ".$_ if($.!=0);END{foreach (sort keys %a){print $a{$_}}}' temp
 11 aa ww
 22 bb kk
 13 cc ll
>