sed

 Name                    Last modified      Size  Description
 Parent Directory                             -   
 useful/                 2021-11-12 10:38    -   
 posix/                  2021-05-24 19:47    -   
 oneliners/              2021-12-25 03:53    -   
 intro/                  2021-12-21 21:57    -   
 gnu/                    2021-05-24 19:48    -   
 barnett/                2021-10-23 16:01    -   

split to many files?

not even sed, just ed