It is a Linux program called Lilypond. The craziest part about getting used to it is that you input the music in a text file, then run the program and it generates it. I plugged in one of my counterpoint examples I did from a class awhile ago.

The input file looks like this:

#(set-default-paper-size "letter")
\version "2.12.2"
\header {
title = "Holst"
composer = "Jesse Talbot"
tagline = ""
}
info = {
\key ees \major
\time 3/4
\partial 4
}
soprano = \relative c' {\info \clef treble ees4 f2 c'4 bes2 g4 ees f2 d bes4 c2 d4 g f2 aes4 g bes aes c bes ees d2 ees2. }
alto = \relative c' {\info \clef treble bes4 bes2 c8 d ees2 d4 c c2 bes g4 g2 bes4 c c2 c4 bes2 c ees4 aes f2 g2. }
tenor = \relative c {\info \clef bass ees4 d ees f g aes bes8 aes g4 aes g f2 ees4 ees f g ees aes g f d2 ees g4 c bes2 bes2. }
bass = \relative c {\info \clef bass g8 aes bes2 aes4 ees2 g4 c aes2 bes8[ aes] g[ f] ees4 c' bes8 aes g4 c f,2 f4 g2 aes ees'4 aes, bes8[ aes] g[ f] ees2. }
top = {\new Staff < <{ \soprano \bar "|."} \\ {\alto \bar "|."} >> }
bottom = {\new Staff < < {\tenor \bar "|."} \\ {\bass \bar "|."} >> }
\new GrandStaff < < \top \bottom >>


When that is entered into the program this is what I get.

It can also generate midi files, pretty much rendering the need for me to buy any notation software completely moot. Which now means I no longer need Windows.

If you are a musician I highly recommend Ubuntu Studio. It is a version of Ubuntu that comes pre-installed with a lot of software aimed at musicians. Sure it takes a little bit of getting used to, but it is all open source software. No company is going to shove their propriatery rights down your throat, and it doesn’t cost anything.