Software installation to Ubuntu Cainiao

This article aims to solve some troubles in installing software by using apt-get in Ubuntu, for example: what should I do if JDK does not exist in the new repository? When installing a new software, the system prompts that the software already exists and is later... this article aims to solve some troubles in installing software by using apt-get in ubuntu as a whole. for example, what should I do if JDK is no longer installed in the new repository? When installing a new software, the system prompts that the software already exists and is later than the original version. what should I do? What should I do if I cannot uninstall the installed software? What should I do if I cannot remember the software name? The repository will be modified (normally, the xxx software is not provided officially or the yyyy library is not maintained officially) to back up the previous (sudo cp/etc/apt/sources. list/etc/apt/sources. list. modify the current sudo apt-get updatesudo apt-get upgrade to delete the software (usually to install a new version) sudo cp/etc/apt/sources. list/etc/apt/sources. list. bak clears the current sources. list content sudo apt-get updatesudo apt-get upgradesudo apt-get remove yourSoftwaresudo cp/etc/apt/sources. list. bak/etc/apt/sources. list sudo apt-get updatesudo apt-get upgrade will install the software (find the software you want through massive search and install it) sudo apt-cache search 'parts of yourSoftware name' sudo apt-get install 'fullname of yoursoft' by Ihavegotyou