Add spaces to first line and another amount of spaces to all other lines

I have a file where i need to put 7 spaces for the first line and 3 spaces for all the other lines.

So i did this (i put 1d to ignore the first line) :

sed -i '1 s/^/       /' $f
sed -i '1d s/^/   /' $f

It works for the first line spaces but the other one gives me this error :

sed: -e expression #1, char 4: extra characters after command

>Solution :

sed '
  # more spaces for the first line
  1s/^/              /
  # less spaces for all the other lines.
  1!s/^/   /
'

You can learn sed at https://www.grymoire.com/Unix/Sed.html#uh-25 https://www.gnu.org/software/sed/manual/sed.html .

You could also do like subtraction, add 4 spaces on first line and then 3 spaces everywhere. 1s/^/ /;s/^/ /