The man page for
apt-get has the following information -
remove is identical to install except that packages are removed
instead of installed. Note that removing a package leaves its
configuration files on the system. If a plus sign is appended to
the package name (with no intervening space), the identified
package will be installed instead of removed.
purge is identical to remove except that packages are removed and
purged (any configuration files are deleted too).
Therefore, if you wish to delete all the configuration files of a particular package along with it,
purge is the better option. However, if you wish to retain the configuration files,
remove should be used.
-y, --yes, --assume-yes
Automatic yes to prompts; assume "yes" as answer to all prompts and
run non-interactively. If an undesirable situation, such as
changing a held package, trying to install a unauthenticated
package or removing an essential package occurs then apt-get will
abort. Configuration Item: APT::Get::Assume-Yes.
-y flag does not remove dependencies but instead skips the user confirmation for the removal of the package, assuming it as a 'Yes' in the Y/N prompt.
For removing a package that is causing problems or need not be installed again, the best option is -
apt-get purge <packagename>
This is because if the configuration files for an application have been modified in a way that caused errors,
purge will remove them, effectively making the subsequent install appear as a fresh install.
NOTE : The
purge option does not apply to packages that hold configuration files inside the user's home folder. Refer to this answer for additional details.