If gnat is not installed, install it (on linux) using something similar to
sudo apt-get install gnat-4.6
write the following code in file called hello_world.adb
with ada.text_io; use ada.text_io; procedure hello_world is begin put_line("hello world"); end hello_world;
compile using
gnatmake hello_world.adb gcc-4.6 -c hello_world.adb gnatbind -x hello_world.ali gnatlink hello_world.ali
Run it using ./hello_world