[Ubuntu] Ubuntu backports

$ apt-cache madison ninja-build
ninja-build | 1.7.1-1~ubuntu16.04.1 | http://us.archive.ubuntu.com/ubuntu xenial-backports/universe amd64 Packages
ninja-build | 1.5.1-0.1ubuntu1 | http://us.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
ninja-build | 1.3.4-1.1 | http://ua.archive.ubuntu.com/ubuntu trusty/universe Sources



ninja-build package has 2 version

xenial : 1.5.1-0.1ubuntu1
xenial-backports : 1.7.1-1~ubuntu16.04.1


$ apt install ninja-build ==> install xenial : 1.5.1-0.1ubuntu1

$ apt install ninja-build/xenial-backports ==> install 1.7.1-1~ubuntu16.04.1



xenial-backports : ubuntu xenial official backports

=> every package does not have backports version.

=> https://packages.ubuntu.com/xenial-backports/allpackages



$ apt install ninja-build/xenial-backports

Reading package lists... Done
Building dependency tree
Reading state information... Done
Selected version '1.7.1-1~ubuntu16.04.1' (Ubuntu:16.04/xenial-backports [amd64]) for 'ninja-build'
The following NEW packages will be installed:
ninja-build
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 91.4 kB of archives.
After this operation, 293 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu xenial-backports/universe amd64 ninja-build amd64 1.7.1-1~ubuntu16.04.1 [91.4 kB]
Fetched 91.4 kB in 1s (76.8 kB/s)
Selecting previously unselected package ninja-build.
(Reading database ... 276265 files and directories currently installed.)
Preparing to unpack .../ninja-build_1.7.1-1~ubuntu16.04.1_amd64.deb ...
Unpacking ninja-build (1.7.1-1~ubuntu16.04.1) ...
Processing triggers for doc-base (0.10.7) ...
Processing 1 added doc-base file...
Processing triggers for man-db (2.7.5-1) ...
Setting up ninja-build (1.7.1-1~ubuntu16.04.1) ...