前一段時間在ubuntu 12.10上安裝軟體。系統的apt在別人裝軟體失敗後變得很奇怪，總是提示一些奇怪的資訊。不管怎麼樣，就是不幹活！

所以，有了這篇內容。

一、通常情況下，在安裝軟體的時候(比如apache2)，執行

sudo apt-get install apache2

二、如果沒有正確執行，可能是系統安裝後軟體列表中內容較少不包含這些軟體，而且沒有更新。

這時候，需要執行

sudo apt-get update

三、如果需要最新版本的軟體執行

sudo apt-get dist-upgrade

然後就可以 

sudo apt-get install apache2

四、如果安裝過程出現錯誤，再次執行apt-get的時候會提示Error

執行 sudo apt-get remove apache2 刪除

然後再執行第一步。

NAME
       apt-get - APT package handling utility -- command-line interface


SYNOPSIS
       apt-get [-asqdyfmubV] [-o=config_string] [-c=config_file]
               [-t=target_release] [-a=architecture] {update | upgrade |
               dselect-upgrade | dist-upgrade |
               install pkg [{=pkg_version_number | /target_release}]...  |
               remove pkg...  | purge pkg...  |
               source pkg [{=pkg_version_number | /target_release}]...  |
               build-dep pkg [{=pkg_version_number | /target_release}]...  |
               download pkg [{=pkg_version_number | /target_release}]...  |
               check | clean | autoclean | autoremove | {-v | --version} |
               {-h | --help}}


DESCRIPTION
       apt-get is the command-line tool for handling packages, and may be
       considered the user's "back-end" to other tools using the APT library.
       Several "front-end" interfaces exist, such as dselect(1), aptitude(8),
       synaptic(8) and wajig(1).


       Unless the -h, or --help option is given, one of the commands below
       must be present.


       update
           update is used to resynchronize the package index files from their
           sources. The indexes of available packages are fetched from the
           location(s) specified in /etc/apt/sources.list. For example, when
           using a Debian archive, this command retrieves and scans the
           Packages.gz files, so that information about new and updated
           packages is available. An update should always be performed before
           an upgrade or dist-upgrade. Please be aware that the overall
           progress meter will be incorrect as the size of the package files
           cannot be known in advance.


       upgrade
           upgrade is used to install the newest versions of all packages
           currently installed on the system from the sources enumerated in
           /etc/apt/sources.list. Packages currently installed with new
           versions available are retrieved and upgraded; under no
           circumstances are currently installed packages removed, or packages
           not already installed retrieved and installed. 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.


       dist-upgrade
           dist-upgrade in addition to performing the function of upgrade,
           also intelligently handles changing dependencies with new versions
           of packages; apt-get has a "smart" conflict resolution system, and
           it will attempt to upgrade the most important packages at the
           expense of less important ones if necessary. The dist-upgrade
           command may therefore remove some packages. The
           /etc/apt/sources.list file contains a list of locations from which
           to retrieve desired package files. See also apt_preferences(5) for
           a mechanism for overriding the general settings for individual
           packages.


       dselect-upgrade
           dselect-upgrade is used in conjunction with the traditional Debian
           packaging front-end, dselect(1).  dselect-upgrade follows the
           changes made by dselect(1) to the Status field of available
           packages, and performs the actions necessary to realize that state
           (for instance, the removal of old and the installation of new
           packages).


       install
           install is followed by one or more packages desired for
           installation or upgrading. Each package is a package name, not a
           fully qualified filename (for instance, in a Debian system,
           apt-utils would be the argument provided, not
           apt-utils_0.9.7.5ubuntu5_amd64.deb). All packages required by the
           package(s) specified for installation will also be retrieved and
           installed. The /etc/apt/sources.list file is used to locate the
           desired packages. If a hyphen is appended to the package name (with
           no intervening space), the identified package will be removed if it
           is installed. Similarly a plus sign can be used to designate a
           package to install. These latter features may be used to override
           decisions made by apt-get's conflict resolution system.


           A specific version of a package can be selected for installation by
           following the package name with an equals and the version of the
           package to select. This will cause that version to be located and
           selected for install. Alternatively a specific distribution can be
           selected by following the package name with a slash and the version
           of the distribution or the Archive name (stable, testing,
           unstable).


           Both of the version selection mechanisms can downgrade packages and
           must be used with care.


           This is also the target to use if you want to upgrade one or more
           already-installed packages without upgrading every package you have
           on your system. Unlike the "upgrade" target, which installs the
           newest version of all currently installed packages, "install" will
           install the newest version of only the package(s) specified. Simply
           provide the name of the package(s) you wish to upgrade, and if a
           newer version is available, it (and its dependencies, as described
           above) will be downloaded and installed.


           Finally, the apt_preferences(5) mechanism allows you to create an
           alternative installation policy for individual packages.


           If no package matches the given expression and the expression
           contains one of '.', '?' or '*' then it is assumed to be a POSIX
           regular expression, and it is applied to all package names in the
           database. Any matches are then installed (or removed). Note that
           matching is done by substring so 'lo.*' matches 'how-lo' and
           'lowest'. If this is undesired, anchor the regular expression with
           a '^' or '$' character, or create a more specific regular
           expression.


       remove
           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
           purge is identical to remove except that packages are removed and
           purged (any configuration files are deleted too).


       source
           source causes apt-get to fetch source packages. APT will examine
           the available packages to decide which source package to fetch. It
           will then find and download into the current directory the newest
           available version of that source package while respecting the
           default release, set with the option APT::Default-Release, the -t
           option or per package with the pkg/release syntax, if possible.


           Source packages are tracked separately from binary packages via
           deb-src lines in the sources.list(5) file. This means that you will
           need to add such a line for each repository you want to get sources
           from; otherwise you will probably get either the wrong (too old/too
           new) source versions or none at all.


           If the --compile option is specified then the package will be
           compiled to a binary .deb using dpkg-buildpackage for the
           architecture as defined by the --host-architecture option. If
           --download-only is specified then the source package will not be
           unpacked.


           A specific source version can be retrieved by postfixing the source
           name with an equals and then the version to fetch, similar to the
           mechanism used for the package files. This enables exact matching
           of the source package name and version, implicitly enabling the
           APT::Get::Only-Source option.


           Note that source packages are not installed and tracked in the dpkg
           database like binary packages; they are simply downloaded to the
           current directory, like source tarballs.


       build-dep
           build-dep causes apt-get to install/remove packages in an attempt
           to satisfy the build dependencies for a source package. By default
           the dependencies are satisfied to build the package natively. If
           desired a host-architecture can be specified with the
           --host-architecture option instead.


       check
           check is a diagnostic tool; it updates the package cache and checks
           for broken dependencies.


       download
           download will download the given binary package into the current
           directory.


       clean
           clean clears out the local repository of retrieved package files.
           It removes everything but the lock file from
           /var/cache/apt/archives/ and /var/cache/apt/archives/partial/. When
           APT is used as a dselect(1) method, clean is run automatically.
           Those who do not use dselect will likely want to run apt-get clean
           from time to time to free up disk space.


       autoclean
           Like clean, autoclean clears out the local repository of retrieved
           package files. The difference is that it only removes package files
           that can no longer be downloaded, and are largely useless. This
           allows a cache to be maintained over a long period without it
           growing out of control. The configuration option
           APT::Clean-Installed will prevent installed packages from being
           erased if it is set to off.


       autoremove
           autoremove is used to remove packages that were automatically
           installed to satisfy dependencies for other packages and are now no
           longer needed.


       changelog
           changelog downloads a package changelog and displays it through
           sensible-pager. The server name and base directory is defined in
           the APT::Changelogs::Server variable (e.g.
           packages.debian.org/changelogs[1] for Debian or
           changelogs.ubuntu.com/changelogs[2] for Ubuntu). By default it
           displays the changelog for the version that is installed. However,
           you can specify the same options as for the install command.


OPTIONS
       All command line options may be set using the configuration file, the
       descriptions indicate the configuration option to set. For boolean
       options you can override the config file by using something like
       -f-,--no-f, -f=no or several other variations.


       --no-install-recommends
           Do not consider recommended packages as a dependency for
           installing. Configuration Item: APT::Install-Recommends.


       --install-suggests
           Consider suggested packages as a dependency for installing.
           Configuration Item: APT::Install-Suggests.


       -d, --download-only
           Download only; package files are only retrieved, not unpacked or
           installed. Configuration Item: APT::Get::Download-Only.


       -f, --fix-broken
           Fix; attempt to correct a system with broken dependencies in place.
           This option, when used with install/remove, can omit any packages
           to permit APT to deduce a likely solution. If packages are
           specified, these have to completely correct the problem. The option
           is sometimes necessary when running APT for the first time; APT
           itself does not allow broken package dependencies to exist on a
           system. It is possible that a system's dependency structure can be
           so corrupt as to require manual intervention (which usually means
           using dselect(1) or dpkg --remove to eliminate some of the
           offending packages). Use of this option together with -m may
           produce an error in some situations. Configuration Item:
           APT::Get::Fix-Broken.


       -m, --ignore-missing, --fix-missing
           Ignore missing packages; if packages cannot be retrieved or fail
           the integrity check after retrieval (corrupted package files), hold
           back those packages and handle the result. Use of this option
           together with -f may produce an error in some situations. If a
           package is selected for installation (particularly if it is
           mentioned on the command line) and it could not be downloaded then
           it will be silently held back. Configuration Item:
           APT::Get::Fix-Missing.


       --no-download
           Disables downloading of packages. This is best used with
           --ignore-missing to force APT to use only the .debs it has already
           downloaded. Configuration Item: APT::Get::Download.


       -q, --quiet
           Quiet; produces output suitable for logging, omitting progress
           indicators. More q's will produce more quiet up to a maximum of 2.
           You can also use -q=# to set the quiet level, overriding the
           configuration file. Note that quiet level 2 implies -y; you should
           never use -qq without a no-action modifier such as -d, --print-uris
           or -s as APT may decide to do something you did not expect.
           Configuration Item: quiet.


       -s, --simulate, --just-print, --dry-run, --recon, --no-act
           No action; perform a simulation of events that would occur but do
           not actually change the system. Configuration Item:
           APT::Get::Simulate.


           Simulated runs performed as a user will automatically deactivate
           locking (Debug::NoLocking), and if the option
           APT::Get::Show-User-Simulation-Note is set (as it is by default) a
           notice will also be displayed indicating that this is only a
           simulation. Runs performed as root do not trigger either NoLocking
           or the notice - superusers should know what they are doing without
           further warnings from apt-get.


           Simulated runs print out a series of lines, each representing a
           dpkg operation: configure (Conf), remove (Remv) or unpack (Inst).
           Square brackets indicate broken packages, and empty square brackets
           indicate breaks that are of no consequence (rare).


       -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.


       --assume-no
           Automatic "no" to all prompts. Configuration Item:
           APT::Get::Assume-No.


       -u, --show-upgraded
           Show upgraded packages; print out a list of all packages that are
           to be upgraded. Configuration Item: APT::Get::Show-Upgraded.


       -V, --verbose-versions
           Show full versions for upgraded and installed packages.
           Configuration Item: APT::Get::Show-Versions.


       -a, --host-architecture
           This option controls the architecture packages are built for by
           apt-get source --compile and how cross-builddependencies are
           satisfied. By default is it not set which means that the host
           architecture is the same as the build architecture (which is
           defined by APT::Architecture). Configuration Item:
           APT::Get::Host-Architecture


       -b, --compile, --build
           Compile source packages after downloading them. Configuration Item:
           APT::Get::Compile.


       --ignore-hold
           Ignore package holds; this causes apt-get to ignore a hold placed
           on a package. This may be useful in conjunction with dist-upgrade
           to override a large number of undesired holds. Configuration Item:
           APT::Ignore-Hold.


       --no-upgrade
           Do not upgrade packages; when used in conjunction with install,
           no-upgrade will prevent packages on the command line from being
           upgraded if they are already installed. Configuration Item:
           APT::Get::Upgrade.


       --only-upgrade
           Do not install new packages; when used in conjunction with install,
           only-upgrade will install upgrades for already installed packages
           only and ignore requests to install new packages. Configuration
           Item: APT::Get::Only-Upgrade.


       --force-yes
           Force yes; this is a dangerous option that will cause apt to
           continue without prompting if it is doing something potentially
           harmful. It should not be used except in very special situations.
           Using force-yes can potentially destroy your system! Configuration
           Item: APT::Get::force-yes.


       --print-uris
           Instead of fetching the files to install their URIs are printed.
           Each URI will have the path, the destination file name, the size
           and the expected MD5 hash. Note that the file name to write to will
           not always match the file name on the remote site! This also works
           with the source and update commands. When used with the update
           command the MD5 and size are not included, and it is up to the user
           to decompress any compressed files. Configuration Item:
           APT::Get::Print-URIs.


       --purge
           Use purge instead of remove for anything that would be removed. An
           asterisk ("*") will be displayed next to packages which are
           scheduled to be purged.  remove --purge is equivalent to the purge
           command. Configuration Item: APT::Get::Purge.


       --reinstall
           Re-install packages that are already installed and at the newest
           version. Configuration Item: APT::Get::ReInstall.


       --list-cleanup
           This option is on by default; use --no-list-cleanup to turn it off.
           When it is on, apt-get will automatically manage the contents of
           /var/lib/apt/lists to ensure that obsolete files are erased. The
           only reason to turn it off is if you frequently change your sources
           list. Configuration Item: APT::Get::List-Cleanup.


       -t, --target-release, --default-release
           This option controls the default input to the policy engine; it
           creates a default pin at priority 990 using the specified release
           string. This overrides the general settings in
           /etc/apt/preferences. Specifically pinned packages are not affected
           by the value of this option. In short, this option lets you have
           simple control over which distribution packages will be retrieved
           from. Some common examples might be -t '2.1*', -t unstable or -t
           sid. Configuration Item: APT::Default-Release; see also the
           apt_preferences(5) manual page.


       --trivial-only
           Only perform operations that are 'trivial'. Logically this can be
           considered related to --assume-yes; where --assume-yes will answer
           yes to any prompt, --trivial-only will answer no. Configuration
           Item: APT::Get::Trivial-Only.


       --no-remove
           If any packages are to be removed apt-get immediately aborts
           without prompting. Configuration Item: APT::Get::Remove.


       --auto-remove
           If the command is either install or remove, then this option acts
           like running the autoremove command, removing unused dependency
           packages. Configuration Item: APT::Get::AutomaticRemove.


       --only-source
           Only has meaning for the source and build-dep commands. Indicates
           that the given source names are not to be mapped through the binary
           table. This means that if this option is specified, these commands
           will only accept source package names as arguments, rather than
           accepting binary package names and looking up the corresponding
           source package. Configuration Item: APT::Get::Only-Source.


       --diff-only, --dsc-only, --tar-only
           Download only the diff, dsc, or tar file of a source archive.
           Configuration Item: APT::Get::Diff-Only, APT::Get::Dsc-Only, and
           APT::Get::Tar-Only.


       --arch-only
           Only process architecture-dependent build-dependencies.
           Configuration Item: APT::Get::Arch-Only.


       --allow-unauthenticated
           Ignore if packages can't be authenticated and don't prompt about
           it. This is useful for tools like pbuilder. Configuration Item:
           APT::Get::AllowUnauthenticated.


       -h, --help
           Show a short usage summary.


       -v, --version
           Show the program version.


       -c, --config-file
           Configuration File; Specify a configuration file to use. The
           program will read the default configuration file and then this
           configuration file. If configuration settings need to be set before
           the default configuration files are parsed specify a file with the
           APT_CONFIG environment variable. See apt.conf(5) for syntax
           information.


       -o, --option
           Set a Configuration Option; This will set an arbitrary
           configuration option. The syntax is -o Foo::Bar=bar.  -o and
           --option can be used multiple times to set different options.


FILES
       /etc/apt/sources.list
           Locations to fetch packages from. Configuration Item:
           Dir::Etc::SourceList.


       /etc/apt/sources.list.d/
           File fragments for locations to fetch packages from. Configuration
           Item: Dir::Etc::SourceParts.


       /etc/apt/apt.conf
           APT configuration file. Configuration Item: Dir::Etc::Main.


       /etc/apt/apt.conf.d/
           APT configuration file fragments. Configuration Item:
           Dir::Etc::Parts.


       /etc/apt/preferences
           Version preferences file. This is where you would specify
           "pinning", i.e. a preference to get certain packages from a
           separate source or from a different version of a distribution.
           Configuration Item: Dir::Etc::Preferences.


       /etc/apt/preferences.d/
           File fragments for the version preferences. Configuration Item:
           Dir::Etc::PreferencesParts.


       /var/cache/apt/archives/
           Storage area for retrieved package files. Configuration Item:
           Dir::Cache::Archives.


       /var/cache/apt/archives/partial/
           Storage area for package files in transit. Configuration Item:
           Dir::Cache::Archives (partial will be implicitly appended)


       /var/lib/apt/lists/
           Storage area for state information for each package resource
           specified in sources.list(5) Configuration Item: Dir::State::Lists.


       /var/lib/apt/lists/partial/
           Storage area for state information in transit. Configuration Item:
           Dir::State::Lists (partial will be implicitly appended)


SEE ALSO
       apt-cache(8), apt-cdrom(8), dpkg(1), dselect(1), sources.list(5),
       apt.conf(5), apt-config(8), apt-secure(8), The APT User's guide in
       /usr/share/doc/apt-doc/, apt_preferences(5), the APT Howto.


DIAGNOSTICS
       apt-get returns zero on normal operation, decimal 100 on error.


BUGS
       APT bug page[3]. If you wish to report a bug in APT, please see
       /usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.


AUTHORS
       Jason Gunthorpe


       APT team


NOTES
        1. packages.debian.org/changelogs
           http://packages.debian.org/changelogs


        2. changelogs.ubuntu.com/changelogs
           http://changelogs.ubuntu.com/changelogs


        3. APT bug page
           http://bugs.debian.org/src:apt