APT usage in Ubuntu

How to directly find the software you want to install under Ubuntu. For example, I want to install Tomcat, but I don't know which version is in Ubuntu or what I need to install, but I can confirm that I have installed tomcat. Then I can use the search command: for example: $ apt-cache search Tomcat then I will get the following results: libtomcat5-java-Java Servlet Engine -- core Libraries

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In this way, I know that Ubuntu's software library contains Tomcat 5, so I can use $ apt-Get install tomcat5 to install apt from Debian GNU/Linux.

Similarly, APT has many commands available:
(1) apt-cache search: we can use this command to search for upgrade packages, for example, Apt-cache search httpd.
(2) apt-Cache show package obtains package information, such as description, size, and version.
(3) apt-Cache depends dependency: we can use this command to view all dependency files of the software package, for example: APT-Cache depends httpd

(4) apt-Cache rdepends package is used to check which packages are dependent on this package.
(5) apt-Get clean: When the installation kit is installed using the apt-Get install command, the downloaded RPM will be placed in/var/Cache/APT/archives, you can clear the apt-Get clean command to avoid occupying hard disk space.
(6) apt-Get remove: for example, Apt-Get remove httpd will be removed. If there is a dependency suite, APT will also be removed.
(7) apt-Get Update update source. It mainly updates apt information sources.
(8) sudo apt-Get upgrade Update installed packages
(9) apt-Get source package download the source code of the package

 

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