# Centre text for an 80-column device.
# Casper Boden-Cummins <casper@wollery.demon.co.uk>

sed -n '
# remove leading and trailing blanks
s/^[	 ]*\(.*[^	 ]\).*$/\1/

# append 80 spaces
s/$/                                                                               /

# chop character 80 onwards
s/^\(.\{80\}\).*/\1/

# prefix string with half the trailing spaces
s/^\(.*[^ ]\)\( *\)\(\2\)/\2\1/
p
'