awk '{$2="#"$2;print $0}' your_file
This will add # to the start of the second (space-separated) column regardless of which position it occurs at.sed -r -e 's/^.{15}/&#/' fileInsert '#' in position 15### erro Nats orbit nats stop orbit nats setup orbit services reload orbit services restart all ls -lh /var/orbini/system/incdt/