Нуждаюсь в помощи “sudo: add-apt-repository: команда, не найденная”

Существует много сообщений "add-apt-repository" там, но я думаю, что видел и попробовал решения в большинстве из них.

Я пытаюсь установить Java на Сервере Ubuntu 12.04. Некоторый ищущий вывод к наиболее распространенному решению ниже:

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer

Однако, когда я работаю

sudo add-apt-repository ppa:webupd8team/java

Я получаю следующую ошибку:

sudo: add-apt-repository: command not found

Так, больше поиска и поиска и устранения неисправностей привели меня к следующему:

sudo apt-get install software-properties-common

Который дает мне (теперь, по крайней мере - в первый раз, когда это на самом деле установило пакет):

0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Другой совет предположил, что следующее могло бы быть необходимо:

sudo apt-get install python-software-properties

Который дает следующую ошибку:

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 python-software-properties : Depends: python-pycurl but it is not installable
E: Unable to correct problems, you have held broken packages.

Таким образом, я попробовал:

sudo apt-get install python-pycur

и получите это:

This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'python-pycurl' has no installation candidate

Отчасти застрявший теперь. Какие-либо идеи, куда пойти затем?

На Thomas W. 's предложение, вот содержание/etc/apt/sources.list:

# deb cdrom:[Ubuntu-Server 12.04.5 LTS _Precise Pangolin_ - Release i386 (20140806.1)]/ precise main restricted

#deb cdrom:[Ubuntu-Server 12.04.5 LTS _Precise Pangolin_ - Release i386 (20140806.1)]/ precise main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ precise universe
deb-src http://us.archive.ubuntu.com/ubuntu/ precise universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu precise-security main restricted
deb-src http://security.ubuntu.com/ubuntu precise-security main restricted

Кроме того, результаты sudo Кв. - добираются, обновление может быть полезным:

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/main/source/Sources  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/restricted/source/Sources  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/universe/source/Sources  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/multiverse/source/Sources  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/main/binary-i386/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/restricted/binary-i386/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/universe/binary-i386/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/multiverse/binary-i386/Packages  Hash Sum mismatch

E: Some index files failed to download. They have been ignored, or old ones used instead.