Count pacman updates and display in polybar

README.md

Count updates

Checks for pacman updates every hour, and echoes the update count to /var/local/countupdates/count.

Polybar can then read this file and display the results.

Prerequisites

• pacman-contrib

Files

systemd

• /usr/local/lib/systemd/system/checkupdates.service
• /usr/local/lib/systemd/system/checkupdates.timer

polybar

• ~/.config/polybar/scripts/count-updates.sh
• ~/.config/polybar/config

pacman

• /etc/pacman.d/hooks/countupdates.hook

checkupdates.service

[Unit]
Description=Count how many updates are available

[Service]
Type=oneshot
ExecStart=/usr/bin/sh -c '/usr/bin/checkupdates | wc -l > /var/local/countupdates/count'

checkupdates.timer

[Unit]
Description=Count how many updates are available

[Timer]
OnCalendar=hourly
Unit=checkupdates.service

[Install]
WantedBy=timers.target

config

[module/count-updates]
type = custom/script
exec = ~/.config/polybar/scripts/count-updates.sh
interval = 10

count-updates.sh

#!/bin/sh

if [ -s /var/local/countupdates/count ] ; then
    updates=$(cat /var/local/countupdates/count)
else
    updates=0
fi

if [ "$updates" -gt 0 ]; then
    echo "# $updates"
else
    echo ""
fi

countupdates.hook

[Trigger]
Operation = Upgrade
Type = Package
Target = *

[Action]
Description = Count the number of packages ready for upgrade.
When = PostTransaction
Exec = sh -c '/usr/bin/checkupdates | wc -l > /var/local/countupdates/count'

Great work, but a little over-engineered.

polybar will run it by itself or throw it on a cron. No need for systemd timers

#!/bin/bash

# provided by pacman-contrib
checkupdates | wc -l

I agree cron would be a lot simpler than systemd timers. That choice was more of a learning exercise for systemd. As for why I'm storing the update count in a file rather than running checkupdates directly from Polybar:

• If I'm on a laptop away from wifi, I don't end up with ERROR: Cannot fetch updates in my bar
• I have a pacman hook that refreshes the count after it's done installing updates, so Polybar can frequently refresh the update count and the update indicator quickly disappears after pacman installs updates

Ha, makes sense! Sorry for necro-ing a two year old gist.

You can easily fix the issue for the ERROR: Cannot fetch updates by simply ignoring it using the same one @wbollock suggested but better.

checkupdates 2>/dev/null | wc -l

It's way superior and more convenient then running a whole service and timer for it.