will result in john getting an email containing the result of a lookup for Susan in the phonebook.

Question

Add a -m command-line option to rolo to make it easy to look up someone and have the result emailed to the specified recipient. So
rolo -m john Susan
will result in john getting an email containing the result of a lookup for Susan in the phonebook.

Answer 1

This is most easily done by adding the following block of code (or its equivalent) immediately after the test for the existence of the PHONEBOOK at the top of rolo:
# if the user specifies -m addr then email the result of the lookup to
# the specified recipient

if [ "$1" = "-m" ] ; then
recipient="$2"
shift 2
if [ -z "$recipient" ] ; then
echo "Error: -m requires an email recipient address"
exit 1
fi
$lu "$@" | mail -s "rolo output" $recipient
exit 0
fi