[Classiccity-pm] substitutions

[Linda Dubes Law]

I have a file that has a bunch of lines in it with emails.  Sometimes there is one email per line and others there are up to 6 emails per line.  I want one email address per line.  Since there is a space between all email addresses, I thought I could do a simple substitute of the space with a new line.  

system ('sed "s/ /\n/g" fileA > fileB');

This does not seem to work well for me.  It removed the spaces but does not add the new line.  

Any ideas for a better way of doing this?  

Thanks 

Linda