Ubuntu software installation, search, uninstall-Apt-Get, Apt-Cache command security

# Apt-Get update -- run this command after modifying/etc/APT/sources. List or/etc/APT/preferences. In addition, you need to regularly run this command to ensure that your package list is up-to-date.

# Apt-Get install packagename -- install a new software package (see aptitude below)
# Apt-Get remove packagename -- uninstall an installed software package (keep the configuration file)
# Apt-Get -- purge remove packagename -- uninstall an installed software package (delete the configuration file)
# Dpkg -- force-all -- purge packagename some software is hard to uninstall and can be used to block other software applications, but it is a little risky.
# Apt-Get autoclean apt will back up installed or unloaded software on the hard disk. If you need space, you can run this command to delete the software you have deleted.
# The apt-Get clean command will also delete the backup of the installed software, but this will not affect the use of the software.
# Apt-Get upgrade -- update all installed software packages
# Apt-Get dist-upgrade -- upgrade the system to the new version.
# Apt-cache search string -- search for strings in the package list
# Dpkg-l package-name-pattern -- list all software packages that match the pattern. If you do not know the full name of the software package, you can use "* package-name-pattern *".

# Aptitude -- view the installed or available software packages in detail. Similar to Apt-Get, aptitude can be called through the command line, but is limited to some commands-the most common commands are installation and uninstallation. Because aptitude knows more information than apt-get, it is more suitable for installation and uninstallation.

# Apt-Cache showpkg pkgs -- displays the package information.
# Apt-Cache dumpavail -- print the list of available software packages.
# Apt-Cache show pkgs -- displays Software Package records, similar to dpkg-print-avail.
# Apt-Cache pkgnames -- print the names of all packages in the package list.
# Dpkg-s file -- the package to which the file belongs.
# Dpkg-l package -- list all files in the software package.
# Apt-file search filename -- search for software packages that contain specific files (not necessarily installed). The file names of these files contain specified strings. Apt-file is an independent software package. You must first install apt-Get install and then run apt-file update. If apt-file search filename outputs too much content, you can try to use apt-file search filename | grep-W filename (only show the names of the complete words in the specified string) or similar methods, such as: APT-File
Search filename | grep/bin/(only files in folders such as/bin or/usr/bin are displayed. If you are looking for a specific execution file, this is helpful ).

Apt-Get update system software package update