I am new to Ubuntu and Git. How I can verify that I have installed git on my machine? When I tried apt-get I got:

root@ubuntu:/home/nebojsa# apt-get install git
Reading package lists... Done
Building dependency tree       
Reading state information... Done
git is already the newest version.
The following packages were automatically installed and are no longer required:
  linux-headers-3.13.0-24 linux-headers-3.13.0-24-generic
  linux-headers-3.13.0-39 linux-headers-3.13.0-39-generic
  linux-headers-3.13.0-40 linux-headers-3.13.0-40-generic
  linux-headers-3.13.0-43 linux-headers-3.13.0-43-generic
  linux-image-3.13.0-24-generic linux-image-3.13.0-39-generic
  linux-image-3.13.0-40-generic linux-image-3.13.0-43-generic
  linux-image-extra-3.13.0-24-generic linux-image-extra-3.13.0-39-generic
  linux-image-extra-3.13.0-40-generic linux-image-extra-3.13.0-43-generic
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 133 not upgraded.

but I don't know where are the packages installed.

Thanks for your help!

Type which git. It should return the path to the executable

If you want to see more details: https://serverfault.com/questions/96964/list-of-files-installed-from-apt-package