Use bkt to cache the output of apt-get update and apt-get -s dist-upgrade

systemd-timer/motd-update.service

@@ -3,4 +3,4 @@ Description=Motd upgradable package count service
 After=network.target
 
 [Service]
-ExecStart=run-parts /etc/update-motd-static.d
+ExecStart=/bin/bash -c "bkt --ttl 1d --force -- sudo apt-get update --quiet=2 && bkt --ttl 1d --force -- sudo apt-get -s dist-upgrade"

systemd-timer/motd-update.timer

@@ -4,6 +4,6 @@ Description=Motd upgradable package count timer - Daily at 8:00PM
 [Timer]
 OnCalendar=*-*-* 20:00
 Persistent=true
- 
+
 [Install]
 WantedBy=timers.target

update-motd.d/20-update

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+function color (){
+  echo "\e[$1m$2\e[0m"
+}
+
+msgColor="38;5;103"
+countColor="38;5;16;48;5;242"
+plurality="packages"
+
+# Count
+bkt --ttl 1d -- sudo apt-get update --quiet=2
+pkgCount="$(bkt --ttl 1d -- sudo apt-get -s dist-upgrade | grep -Po '^\d+(?= upgraded)')"
+
+if (( $pkgCount > 0 )); then
+  countColor="38;5;16;48;5;71"
+fi
+if (( $pkgCount == 1 )); then
+    plurality="package"
+fi
+
+# Message
+msgHeader=$(color $msgColor \*)
+msgCount=$(color $countColor " $pkgCount ")
+msgLabel=$(color $msgColor "$plurality can be upgraded")
+
+echo -e "\n$msgHeader $msgCount $msgLabel\n"
+