Determine when package index was updated.
Ubuntu is using a timestamp file to mark an successfull package index update.
$ cat /etc/apt/apt.conf.d/15update-stamp
APT::Update::Post-Invoke-Success {"touch /var/lib/apt/periodic/update-success-stamp 2>/dev/null || true";};
Inspect current timestamp.
$ stat --format "%y" /var/lib/apt/periodic/update-success-stamp
2022-07-02 17:24:42.233369776 +0000
Update package index.
$ sudo apt update
Hit:1 http://pl.archive.ubuntu.com/ubuntu jammy InRelease Hit:2 http://pl.archive.ubuntu.com/ubuntu jammy-updates InRelease Hit:3 http://pl.archive.ubuntu.com/ubuntu jammy-backports InRelease Hit:4 http://pl.archive.ubuntu.com/ubuntu jammy-security InRelease Reading package lists... Done Building dependency tree... Done Reading state information... Done All packages are up to date.
Inspect updated timestamp file.
$ stat --format "%y" /var/lib/apt/periodic/update-success-stamp
2022-07-02 17:30:13.855014199 +0000
