Personal_Website/content/snippets/seconds-since-last-pacman-sync.md

title	date	tags	draft
Seconds since last pacman sync	2022-06-11T08:45:13Z	archlinux linux pacman	false

Result

We can find out how many seconds ago the last package was installed or updated using pacman by using the following command:

echo $(expr $(date +%s) - $(grep -rn -A 1 %INSTALLDATE% /var/lib/pacman/local/*/desc | grep -oP '\d{10,}$' | sort | tail -1))

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Explanation

Let's dive into the weeds to see how this is built up.

Pacman stores its local cache on your system at /var/lib/pacman/local/. This folder contains a couple files for every package.

Try reading the files for the kernel for example. We are only interested in the installation date, so let's focus on that field.

$ grep -A 1 '%INSTALLDATE%' /var/lib/pacman/local/linux-5.17.5.arch1-1/desc
%INSTALLDATE%
1651693442

By running this on all files in the pacman cache directory and then filtering for numbers, you get to see the entire list of dates for every package.

$ grep -A 1 '%INSTALLDATE%' /var/lib/pacman/local/*/desc | grep -oP '\d{10,}$' | head -5
1642498423
1644184812
1640442731
1640443485
1640443485

Now we just need to sort the entries and pick the highest value. This is the timestamp of our last package installation.

$ grep -rn -A 1 %INSTALLDATE% /var/lib/pacman/local/*/desc | grep -oP '\d{10,}$' | sort | tail -1
1654790640

Now we just have to subtract this timestamp from the current date to get the amount of seconds since the last package installation.

echo $(expr $(date +%s) - $(grep -rn -A 1 %INSTALLDATE% /var/lib/pacman/local/*/desc | grep -oP '\d{10,}$' | sort | tail -1))