Listing 6. /etc/ppp/appear Script

#!/bin/sh

#
# this script causes the ghosting server
# to drift on and off the internet
#

#
# see if we may need to restart diald
#
if ! `ps -ax | grep diald >>/dev/null` ; then

 # if so bring it up
 /etc/ppp/diald-up

# wait for diald to come up
 sleep 5

fi

#
# see if we are already connected to the net
#

if ! `ifconfig | grep "^ppp" >/dev/null` ; then

 # if not, bring link up
 ping -c 1 myisp.net >/dev/null

 # wait for link to come up
 sleep 60

fi

#
# see if we want to come back up
#
# normally I only want to be ghosting Monday
# through Friday from 7a to 6p
#

day=`date +%w`
hour=`date +%H`
if `expr match $day "[123456]" "&" $hour ">" \
	6 "&" $hour "<" 18 >/dev/null` ;
then

 # calculate delay for next up time between 15 and
 # 60 minutes
 nxt=`expr $$ % 45 + 15`

 # append info to file
 echo `date` "Back: $nxt" >> /var/run/ppp.info

 # send info to desired destination
 mail -S ghostship me@myisp me@work\
	< /var/run/ppp.info

 # create an at job to force return
 at now + $nxt minutes <EOF >/dev/null 2>&1
 /etc/ppp/appear
EOF

fi