How to Replace single random line

[digitalmonkeyman]

Can anyone help me on this one? I need to replace the following, and the name is different in each file;

by: Chris Anderson
or
by: John Martin
or
by: Joe Smith

I would like to replace the
'by: name name'
line in multiple files with a blank line
what paramaters do I use?
Thanks

[Abacre]

Go to Batch replace tab, check on "Use regular expressions".
Put into the grid, search for:
^by: .*$

Replace with:
empty string

That's all I verified it works perfectly.