I have some problems with
git-lfs and I think that upgrading to the latest
git can fix this problems. Current version of
git in Debian is
2.1.4, current stable version on official site is
2.6.4. Can I only build from source or maybe can I add some external repository?
As of December 2015, Debian stretch/sid has git version 2.6.4. If you don't want to upgrade your entire distribution, you can look into apt pinning to bring in only git and any necessary dependencies from stretch/sid. However, many Debian folks will tell you this sort of thing is a bad idea, so building from source or waiting/asking for a backport are the only officially recommended approaches.
Backporting git from Debian testing, unstable, or experimental is fairly trivial. See How can I install more recent versions of software than what Debian provides?. Something as simple as
apt-get source -t unstable git, followed up
debuild -uc -us inside the source directory should work. Note that these two commands should be run as user, not root.
You might have to install some build dependencies, though.
apt-get build-dep git will probably work in that case. Note that this command
is run as root, not user.
Please comment if you are trying to do this and need more details.
This worked on a Debian docker container(php:5-apache).
NOTE: This currently(Mar 2018) doesn't work with an error of
RUN echo "deb http://ftp.us.debian.org/debian testing main contrib non-free" >> /etc/apt/sources.list \ && apt-get update \ && apt-get install -y git \ && apt-get clean all
What Svetlin Tonchev suggested would work out of the box only if OP was using Ubuntu, which isn't the case here. However, when running add-apt-repository the added source will depend on the name of your OS. For example, if you go to /etc/apt/sources.list.d/ you might find a file called git-core-ppa-jessie.list (or similar) containing the following lines:
deb http://ppa.launchpad.net/git-core/ppa/ubuntu jessie main
deb-src http://ppa.launchpad.net/git-core/ppa/ubuntu jessie main
However, such repository does not exist and that's why OP got a 404.
A possible solution to this specific issue would be to manually edit the above file and replace jessie with xenial.