There's something wrong with your network mail-transmission software if
it truncates a message on a single "." (or causes the receiver to do so).
The standard is for the mail-sender to prepend any line starting with a
period with another period - i.e., change:
and for the mail receiver to strip off any leading period.
You shouldn't have to do it yourself...
Given that you *do* have the problem, though, there are better ways of
handling it. The one I think preferable is to run "fill" against your
input files before digestifying it. "fill" is a utility that will fold
all your lines to a standard length (with some amount of smarts about
what constitutes a paragraph and when leading spaces should be retained
on lines) - it will break on word boundaries, rather than in the middle
of a text string. The only drawback is that it might not handle some
specially-formatted text correctly - tables, cute signature lines, etc.,
might not work right. The overall simplest method is probably what
you're doing, followed by the sed script "/^\.$/d" which will delete any
line consisting only of a period - or use "s/^\.$/ \<CTL-H>./" to change
it to <SPACE><BackSpace><PERIOD> (neater than doing <SPACE><PERIOD>).