What is the difference between apt-get update and upgrade?
What is the difference between
Which should I run first?
Do any of them automatically run the other?
See: http://askubuntu.com/questions/99033/what-is-the-difference-between-apt-get-upgrade-and-apt-get-dist-upgrade *What is the difference between apt-get upgrade and apt-get dist-upgrade?*
Possible duplicate of: http://askubuntu.com/questions/81585/what-is-dist-upgrade-and-why-does-it-upgrade-more-than-upgrade OR http://askubuntu.com/questions/99033/what-is-the-difference-between-apt-get-upgrade-and-apt-get-dist-upgrade
You should first run
upgrade. Neither of them automatically runs the other.
apt-get updateupdates the list of available packages and their versions, but it does not install or upgrade any packages.
apt-get upgradeactually installs newer versions of the packages you have. After updating the lists, the package manager knows about available updates for the software you have installed. This is why you first want to
Additionally, you can use
apt-get update && apt-get upgradeto do both steps after each other.
Keep in mind that most of the times instead of `apt-get upgrade` what you want to do is `apt-get dist-upgrade`
@TravisR Not really. `dist-upgrade` won't upgrade to a new OS, but will upgrade to a new kernel (common enough) or a different set of dependencies (common enough) or remove dependencies that don't matter after an upgrade (also common). If you're on a home or office system, most of the time you want `dist-upgrade`, not `upgrade`. It's if you are upgrading several systems, or one that you need kept in a well-defined state that you'd want `upgrade`. For "regular" users (their own machine), `dist-upgrade` is the one to go for.
So do you mean that "apt-get upgrade" will do nothing if not followed by "apt-get update"? If this is so, what is the real use of "apt-get update"? Then why the "update" is not included in "upgrade"?
@user22180 that's a very intelligent question. At first glance, it's absurd to separate the methods if both must be called to accomplish the desired function, to actually replace the old packages with the new ones. But you may want to difference between the packages you need to install and the ones you eventually want to upgrade.
@JonHanna what is the difference between OS and kernel ??? (Genuine question)... i have heard that there is no std. def. of OS and that it can be called kernel
@juggernaut1996 you're right, there is no good overall definition. In this case I mean it won't go from e.g. Ubuntu 16.04 to 16.10, but it will upgrade the Linux kernel if the version of Ubuntu you're using updates to use a later on. So here I'm calling Ubuntu the OS.
@TimoKluck How about the difference between `apt-get upgrade` and `apt-get install`?
Well I'm truly confused. It seems `apt-get upgrade` will not install all kernel security patches, but `apt-get install` will. Note that `apt install` does the same thing these days