Ubuntu Upgrade Software and Ubuntu Upgrade System Commands

sudo apt-get update: Upgrade the commands related to the installation package, refresh the list of installable software (but do not do any actual installation actions)
sudo apt-get upgrade: update the installation package (upgrade the software version)
sudo apt-get dist-upgrade: In addition to having all the functions of upgrade, dist-upgrade will handle the dependencies of packages that need to be updated more intelligently than upgrade.
sudo do-release-upgrade: upgrade the system version (upgrade of the Ubuntu version), the official Ubuntu recommended system upgrade method, if you add the parameter -d, you can also upgrade to the development version, but it will be unstable
sudo apt-get autoclean: clean up the old version of the software cache
sudo apt-get clean: clean all software cache

sudo apt-get autoremove: delete orphaned software that is no longer used by the system

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Delete unused old kernels

In Linux, /boot is the place where the system boot files are stored. When ubuntu is installed, a separate partition of 200M is enough, but after the system kernel is updated, the old kernel is still stored in the /boot partition. After several upgrades, it will prompt that there is insufficient /boot space .
We just need to delete the old kernel and free up space.
First check the installed kernel version
dpkg --get-selections |grep linux
Can see the installed version, and the one with image is generally the old version
deinstall represents the old version that has been deleted
install is an old version of the kernel that has not been deleted
uname -r

View current kernel version

sudo apt-get remove linux-image-xxxx
Delete the old version of the kernel, xxx is the kernel version number
To
1. Delete the software
Method 1: If you know the specific name of the software to be deleted, you can use
sudo apt-get remove --purge software name
sudo apt-get autoremove --purge software name

Method 2: If you do not know the specific name of the software to be deleted, you can use
dpkg --get-selections | grep ‘software related name’
sudo apt-get purge A package with core, if there is no package with core, it depends on the situation. 123

2. Clean up residual data
dpkg -l |grep ^rc|awk'{print $2}' |sudo xargs dpkg -P