Comment by oddline

Yikes,

    $ cat rewrite_me 
    #!/bin/bash
    C=$(sed -r 's,^(C.+sed.+)#$,\1,g' ./$0); echo "$C" > $0  #####
    # date

    $ ./rewrite_me 
    Fri 08 May 2020 11:41:52 PM CEST