=item *
-":0,$s/^ "
+C<":0,$s/^ ">
Removes four leading spaces from the entire file (from the first line,
C<0>, to the last line, C<$>).
=item *
-"%s/^ "
+C<"%s/^ ">
A shortcut for the previous item (C<%> specifies the entire file; so
this removes four leading spaces from every line).
=item *
-":.,44s/^ "
+C<":.,44s/^ ">
Removes four leading space from the current line through line 44
(obviously adjust the C<44> to the appropriate value in your example).