/etc/crontab should never be modified. instead use /etc/cron.d to install cron tasks

advanced/pihole.cron

@@ -1,17 +1,3 @@
-# /etc/crontab: system-wide crontab
-# Unlike any other crontab you don't have to run the `crontab'
-# command to install the new version when you edit this file
-# and files in /etc/cron.d. These files also have username fields,
-# that none of the other crontabs do.
-
-SHELL=/bin/sh
-PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
-
-# m h dom mon dow user  command
-17 *    * * *   root    cd / && run-parts --report /etc/cron.hourly
-25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
-47 6    * * 7   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
-52 6    1 * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
 
 # Pi-hole: Update the ad sources once a week on Sunday at 01:59
 #          Download any updates from the ad lists
@@ -24,3 +10,4 @@ PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
 # Pi-hole: Flush the log daily at 11:58 so it doesn't get out of control
 #          Stats will be viewable in the Web interface thanks to the cron job above
 58 11   * * *   root    /usr/local/bin/piholeLogFlush.sh
+

automated install/basic-install.sh

@@ -255,8 +255,11 @@ curl -o /var/www/html/pihole/index.html https://raw.githubusercontent.com/jacobs
 }
 
 installCron(){
-mv /etc/crontab /etc/crontab.orig
-curl -o /etc/crontab https://raw.githubusercontent.com/jacobsalmela/pi-hole/master/advanced/pihole.cron
+curl -o /etc/cron.d/pihole https://raw.githubusercontent.com/jacobsalmela/pi-hole/master/advanced/pihole.cron
+
+# in most cases, cron should pickup pihole automatically but to avoid
+# any edge cases, the service should be restarted.
+service cron restart
 }
 
 installPihole()

automated install/uninstall.sh

@@ -20,8 +20,23 @@ apt-get -y remove --purge dnsmasq
 apt-get -y remove --purge lighttpd php5-common php5-cgi php5
 rm -rf /var/www/html
 rm /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
-rm /etc/crontab
-mv /etc/crontab.orig /etc/crontab
+
+# attempt to preserve backwards compatibility with older versions
+# to gaurentee no additional changes were made to /etc/crontab after
+# the installation of pihole, /etc/crontab.pihole should be permanently
+# preserved.
+# @TODO: debugging statement alerting user of this.
+if [ -f /etc/crontab.orig ]; then
+	mv /etc/crontab /etc/crontab.pihole
+	mv /etc/crontab.orig /etc/crontab
+	service cron restart
+fi
+
+# attempt to preserve backwards compatibility with older versions
+if [ -f /etc/cron.d/pihole ]; then
+	rm /etc/cron.d/pihole
+fi
+
 rm /etc/dnsmasq.conf
 rm -rf /etc/lighttpd/
 rm /var/log/pihole.log