Hi!

vi has perl regular expressions?

If you compile vim with perl support, you can directly execute perl commands inside vim

see also: http://vimdoc.sourceforge.net/htmldoc/if_perl.html

Have fun!

Update Your command would be:

:perldo $_ =~ s/#1/# 1/g;
[download]

with :perldo executing the given command on each line of your file.