I'm following these instructions to install git on my laptop:

http://git-scm.com/download/linux

When I do:

$ sudo apt-get install git-core

This is what my terinal shows:

Reading package lists... Done Building dependency tree Reading

state information... Done The following packages were automatically

installed and are no longer required: libasprintf0c2:i386

libcroco3:i386 libgettextpo0:i386 libgomp1:i386 libunistring0:i386

Use 'apt-get autoremove' to remove them. The following extra packages

will be installed: git git-man liberror-perl Suggested packages:

git-daemon-run git-daemon-sysvinit git-doc git-el git-arch git-cvs

git-svn git-email git-gui gitk gitweb The following NEW packages

will be installed: git git-core git-man liberror-perl 0 upgraded, 4

newly installed, 0 to remove and 0 not upgraded. Need to get 6,825 kB

of archives. After this operation, 15.3 MB of additional disk space

will be used. Do you want to continue [Y/n]? y WARNING: The following

packages cannot be authenticated! liberror-perl git-man git git-core

Install these packages without verification [y/N]? E: Some packages

could not be authenticated lucas@lucas-Inspiron-N5050:~$ sudo apt-get

install git-core Reading package lists... Done Building dependency

tree Reading state information... Done The following packages

were automatically installed and are no longer required:

libasprintf0c2:i386 libcroco3:i386 libgettextpo0:i386 libgomp1:i386

libunistring0:i386 Use 'apt-get autoremove' to remove them. The

following extra packages will be installed: git git-man

liberror-perl Suggested packages: git-daemon-run git-daemon-sysvinit

git-doc git-el git-arch git-cvs git-svn git-email git-gui gitk

gitweb The following NEW packages will be installed: git git-core

git-man liberror-perl 0 upgraded, 4 newly installed, 0 to remove and 0

not upgraded. Need to get 6,825 kB of archives. After this operation,

15.3 MB of additional disk space will be used. Do you want to continue [Y/n]? y WARNING: The following packages cannot be authenticated!
liberror-perl git-man git git-core Install these packages without

verification [y/N]? y Err httpq://py.archive.ubuntu.com/ubuntu/

quantal/main liberror-perl all 0.17-1 Something wicked happened

resolving 'py.archive.ubuntu.com:http' (-5 - No address associated

with hostname) Err httpq://py.archive.ubuntu.com/ubuntu/ quantal/main

git-man all 1:1.7.10.4-1ubuntu1 Something wicked happened resolving

'py.archive.ubuntu.com:http' (-5 - No address associated with

hostname) Err httpq://py.archive.ubuntu.com/ubuntu/ quantal/main git

amd64 1:1.7.10.4-1ubuntu1 Something wicked happened resolving

'py.archive.ubuntu.com:http' (-5 - No address associated with

hostname) Err httpq://py.archive.ubuntu.com/ubuntu/ quantal/main

git-core all 1:1.7.10.4-1ubuntu1 Something wicked happened resolving

'py.archive.ubuntu.com:http' (-5 - No address associated with

hostname) Failed to fetch

httpq://py.archive.ubuntu.com/ubuntu/pool/main/libe/liberror-perl/liberrorperl_0.17-1_all.deb Something wicked happened resolving 'py.archive.ubuntu.com:http' (-5 -

No address associated with hostname) Failed to fetch

httpq://py.archive.ubuntu.com/ubuntu/pool/main/g/git/git-man_1.7.10.4-1ubuntu1_all.deb

Something wicked happened resolving 'py.archive.ubuntu.com:http' (-5 -

No address associated with hostname) Failed to fetch

httpq://py.archive.ubuntu.com/ubuntu/pool/main/g/git/git_1.7.10.4-1ubuntu1_amd64.deb

Something wicked happened resolving 'py.archive.ubuntu.com:http' (-5 -

No address associated with hostname) Failed to fetch

http://py.archive.ubuntu.com/ubuntu/pool/main/g/git/git-core_1.7.10.4-1ubuntu1_all.deb

Something wicked happened resolving 'py.archive.ubuntu.com:http' (-5 -

No address associated with hostname) E: Unable to fetch some archives,

maybe run apt-get update or try with --fix-missing?

How could I install git on Ubuntu 12.10? I can't even do it from the Ubuntu Software Center.

Thanks in advance!