It's "OS X", not "OSX".

(via @solnic)

app/decorators/asciicast_decorator.rb

@@ -88,7 +88,7 @@ class AsciicastDecorator < ApplicationDecorator
     if text =~ /Linux/
       'Linux'
     elsif text =~ /Darwin/
-      'OSX'
+      'OS X'
     else
       text.split(' ', 2)[0]
     end

app/views/home/show.html.slim

@@ -19,7 +19,7 @@
           p
             = link_to 'Start Recording', docs_path('getting-started'), class: 'btn btn-success'
           p
-            ' Supports Linux, Mac OSX and FreeBSD
+            ' Supports Linux, Mac OS X and FreeBSD
 
   section.even
     .container

app/views/pages/contributing.html.slim

@@ -87,7 +87,7 @@
     h2 id="packaging" Packaging
 
     p
-      ' Currently Asciinema recorder can be installed on any Linux, OSX and
+      ' Currently Asciinema recorder can be installed on any Linux, OS X and
         FreeBSD system with <code>pip</code> (because it's a Python package at
         its core).  There are also native packages for Ubuntu and Arch Linux at
         the moment.

spec/decorators/asciicast_decorator_spec.rb

@@ -22,14 +22,14 @@ describe AsciicastDecorator do
         it { should == 'Linux' }
       end
 
-      context 'and the OS is OSX' do
+      context 'and the OS is OS X' do
         before do
           asciicast.user_agent =
             "asciinema/0.9.7 CPython/2.7.4 " \
             "Darwin/10.0.0-i386-64bit"
         end
 
-        it { should == 'OSX' }
+        it { should == 'OS X' }
       end
 
       context 'and the OS is other' do
@@ -57,7 +57,7 @@ describe AsciicastDecorator do
           asciicast.uname = "Darwin local 10.3.0 Darwin Kernel Version 10.3.0"
         end
 
-        it { should == 'OSX' }
+        it { should == 'OS X' }
       end
 
       context "and it's other" do