Ubuntu – apt-get is stuck at “Fetched XXKb in XXsec”

sudo apt-get update fetches Indices of the package list from repositories. But it does so with an order, both for security and to reduce download size of the Package Indices.

For each repository,

First, it tries to match the modification time of the InRelease file (which is an Inline signature file) in the online-repository with the one already downloaded in your computer (if there is any).

• If it finds that the InRelease file is not modified in online-repository, it doesn't proceed to download the index file (Packages.gz etc), which are bigger and actual index, provided that it is already downloaded in your computer. Because not modified signature means index file isn't modified.

• If it finds that the InRelease file's modification date is changed, it will first get the InRelease file. Then again try to match the checksum (found in InRelease file) of to the already downloaded Index. If that matches, it won't download the index. Otherwise, Downloads the Index.

There are more things done behind the scene. But basically in your case, it means, since you just updated package list with sudo apt-get update, It is normal to have shorter output later, because in this shorter time period nothing in the repository has changed.

Check this for further info:

• How do Ign and Hit affect apt-get update
• Secure Apt - Debian Wiki

Software Updater only updates installed apt packages. Installed snap packages are automatically updated separately in the background. You can also update snap packages from the terminal with the following command:

sudo snap refresh  

The sudo snap refresh command updates the specified snaps, or all snaps in the system if none are specified. The results of sudo snap refresh will list the snaps that were refreshed by that command.

Since snap packages are standalone packages that are bundled with everything necessary to install each snap package, it is possible to install a snap package alongside an apt package of the same application and use either or both of them, as well as being possible to mix and match apt and snap packages freely. This is a great convenience when you need to install the latest version of an application. In fact some snap packages such as the node snap (Node.js) are available in multiple versions and you can even install multiple versions of the same software and select which version to use each time you run the software.

If there are multiple versions of the same application installed it can get confusing if they both have the same icon in the Dash, however you can also run any snap package from the terminal with this command:

snap run snap-package-name

If there is a snap package named snap-package-name installed the above command with run it, but it will not run the apt package of the same application.