Updating debian apt
New versions of currently installed packages that cannot be upgraded without changing the install status of another package will be left at their current version.
An update must be performed first so that apt-get knows that new versions of packages are available.
The difference is that it only removes package files that can no longer be downloaded, and are largely useless.
Identical to install except that packages are removed instead of installed.
Several "front-end" interfaces exist, such as synaptic and aptitude.
Used to re-synchronize the package index files from their sources.
The indexes of available packages are fetched from the location(s) specified in /etc/apt/sources.list(5).
An update should always be performed before an upgrade or dist-upgrade.
W: Failed to fetch 404 Not Found W: Failed to fetch 404 Not Found E: Some index files failed to download. Err Could not resolve 'debian.org' Err Could not resolve 'deb.torproject.org' Err Could not resolve 'security.debian.org' Reading package lists... If not, something is broken or it’s a Man in the middle attack, which isn’t that unlikely, since we are updating over Tor exit relays and some of them are malicious. The repository is not updated and the previous index files will be used.