fmt -w600, sed edition

paragraphify.sed

#!/usr/bin/sed -nf
# First line: only hold and skip.
1 { h;d; }
# Line with only spaces: wow, free paragraph information!
/^\s*$/ { s/^.*$//; bfinished }
# Append line to hold space.
H
# Line ends with dot? We have a new paragraph.
/\.$/bfinished
# Render last line
$bfinished
# If we didn't branch to finish, then skip.
# We already have held the pattern anyway.
d
:finished
# One of the above conditions happened. Let's roll.
# Get hold space
x
# Handle hyphenation
s/-\n//g
# Delete newlines
s/\n/ /g
# Add some paragraphing
a\

# Print hold space
p
# Empty hold space
s/.*//g
# Get old pattern space
x
# Squeeze empty lines.
:spacefind
n
/^\s*$/bspacefind
# Hold first non-space only line
h