Set MACOS_VERSION as 0 on non-OSX platforms.

Library/Contributions/cmds/brew-man

@@ -24,7 +24,7 @@ test "$1" = '-l' && {
   exit 0
 }
 
-/usr/bin/which -s ronn || die "You need to \"gem install ronn\" and put it in your path."
+/usr/bin/which ronn &>/dev/null || die "You need to \"gem install ronn\" and put it in your path."
 
 test "$1" = '--server' || \
 test "$1" = '-s' && {

Library/Homebrew/cmd/doctor.rb

@@ -624,7 +624,7 @@ def check_for_multiple_volumes
 end
 
 def check_for_git
-  unless system "/usr/bin/which -s git" then <<-EOS.undent
+  unless which_s "git" then <<-EOS.undent
     Git could not be found in your PATH.
     Homebrew uses Git for several internal functions, and some formulae use Git
     checkouts instead of stable tarballs. You may want to install Git:
@@ -634,7 +634,7 @@ def check_for_git
 end
 
 def check_git_newline_settings
-  return unless system "/usr/bin/which -s git"
+  return unless which_s "git"
 
   autocrlf = `git config --get core.autocrlf`.chomp
   safecrlf = `git config --get core.safecrlf`.chomp
@@ -765,7 +765,7 @@ def check_missing_deps
 end
 
 def check_git_status
-  return unless system "/usr/bin/which -s git"
+  return unless which_s "git"
   HOMEBREW_REPOSITORY.cd do
     unless `git status -s -- Library/Homebrew/ 2>/dev/null`.chomp.empty? then <<-EOS.undent
       You have uncommitted modifications to Homebrew's core.
@@ -794,7 +794,7 @@ end
 
 def check_git_version
   # see https://github.com/blog/642-smart-http-support
-  return unless system "/usr/bin/which -s git"
+  return unless which_s "git"
   `git --version`.chomp =~ /git version (\d)\.(\d)\.(\d)/
 
   if $2.to_i < 6 or $2.to_i == 6 and $3.to_i < 6 then <<-EOS.undent
@@ -806,7 +806,7 @@ def check_git_version
 end
 
 def check_for_enthought_python
-  if system "/usr/bin/which -s enpkg" then <<-EOS.undent
+  if which_s "enpkg" then <<-EOS.undent
     Enthought Python was found in your PATH.
     This can cause build problems, as this software installs its own
     copies of iconv and libxml2 into directories that are picked up by
@@ -816,7 +816,7 @@ def check_for_enthought_python
 end
 
 def check_for_bad_python_symlink
-  return unless system "/usr/bin/which -s python"
+  return unless which_s "python"
   # Indeed Python --version outputs to stderr (WTF?)
   `python --version 2>&1` =~ /Python (\d+)\./
   unless $1 == "2" then <<-EOS.undent

Library/Homebrew/cmd/update.rb

@@ -4,7 +4,7 @@ require 'cmd/untap'
 module Homebrew extend self
 
   def update
-    abort "Please `brew install git' first." unless system "/usr/bin/which -s git"
+    abort "Please `brew install git' first." unless which_s "git"
 
     # ensure GIT_CONFIG is unset as we need to operate on .git/config
     ENV.delete('GIT_CONFIG')

Library/Homebrew/cmd/versions.rb

@@ -2,7 +2,7 @@ require 'formula'
 
 module Homebrew extend self
   def versions
-    raise "Please `brew install git' first" unless system "/usr/bin/which -s git"
+    raise "Please `brew install git` first" unless which_s "git"
     raise "Please `brew update' first" unless (HOMEBREW_REPOSITORY/".git").directory?
 
     raise FormulaUnspecifiedError if ARGV.named.empty?

Library/Homebrew/download_strategy.rb

@@ -90,7 +90,7 @@ class CurlDownloadStrategy < AbstractDownloadStrategy
       safe_system '/usr/bin/tar', 'xf', @tarball_path
       chdir
     when /^\xFD7zXZ\x00/ # xz compressed
-      raise "You must install XZutils: brew install xz" unless system "/usr/bin/which -s xz"
+      raise "You must install XZutils: brew install xz" unless which_s "xz"
       safe_system "xz -dc \"#{@tarball_path}\" | /usr/bin/tar xf -"
       chdir
     when '____pkg'
@@ -326,7 +326,7 @@ class GitDownloadStrategy < AbstractDownloadStrategy
   end
 
   def fetch
-    raise "You must install Git: brew install git" unless system "/usr/bin/which -s git"
+    raise "You must install Git: brew install git" unless which_s "git"
 
     ohai "Cloning #{@url}"
 
@@ -447,7 +447,7 @@ class MercurialDownloadStrategy < AbstractDownloadStrategy
   def cached_location; @clone; end
 
   def fetch
-    raise "You must install Mercurial: brew install mercurial" unless system "/usr/bin/which -s hg"
+    raise "You must install Mercurial: brew install mercurial" unless which_s "hg"
 
     ohai "Cloning #{@url}"
 
@@ -488,8 +488,7 @@ class BazaarDownloadStrategy < AbstractDownloadStrategy
   def cached_location; @clone; end
 
   def fetch
-    raise "You must install bazaar first" \
-          unless system "/usr/bin/which -s bzr"
+    raise "You must install bazaar first" unless which_s "bzr"
 
     ohai "Cloning #{@url}"
     unless @clone.exist?
@@ -532,8 +531,7 @@ class FossilDownloadStrategy < AbstractDownloadStrategy
   def cached_location; @clone; end
 
   def fetch
-    raise "You must install fossil first" \
-          unless system "/usr/bin/which -s fossil"
+    raise "You must install fossil first" unless which_s "fossil"
 
     ohai "Cloning #{@url}"
     unless @clone.exist?

Library/Homebrew/global.rb

@@ -61,10 +61,18 @@ end
 
 HOMEBREW_LOGS = Pathname.new('~/Library/Logs/Homebrew/').expand_path
 
-MACOS_FULL_VERSION = `/usr/bin/sw_vers -productVersion`.chomp
-MACOS_VERSION = /(10\.\d+)(\.\d+)?/.match(MACOS_FULL_VERSION).captures.first.to_f
+if RUBY_PLATFORM =~ /darwin/
+  MACOS_FULL_VERSION = `/usr/bin/sw_vers -productVersion`.chomp
+  MACOS_VERSION = /(10\.\d+)(\.\d+)?/.match(MACOS_FULL_VERSION).captures.first.to_f
+  OS_VERSION = "Mac OS X #{MACOS_FULL_VERSION}"
+  MACOS = true
+else
+  MACOS_FULL_VERSION = MACOS_VERSION = 0
+  OS_VERSION = RUBY_PLATFORM
+  MACOS = false
+end
 
-HOMEBREW_USER_AGENT = "Homebrew #{HOMEBREW_VERSION} (Ruby #{RUBY_VERSION}-#{RUBY_PATCHLEVEL}; Mac OS X #{MACOS_FULL_VERSION})"
+HOMEBREW_USER_AGENT = "Homebrew #{HOMEBREW_VERSION} (Ruby #{RUBY_VERSION}-#{RUBY_PATCHLEVEL}; #{OS_VERSION})"
 
 HOMEBREW_CURL_ARGS = '-qf#LA'
 

Library/Homebrew/utils.rb

@@ -138,7 +138,8 @@ def puts_columns items, star_items=[]
   end
 end
 
-def which cmd
+def which cmd, silent=false
+  cmd += " 2>/dev/null" if silent
   path = `/usr/bin/which #{cmd}`.chomp
   if path.empty?
     nil
@@ -147,15 +148,19 @@ def which cmd
   end
 end
 
+def which_s cmd
+  which cmd, true
+end
+
 def which_editor
   editor = ENV['HOMEBREW_EDITOR'] || ENV['EDITOR']
   # If an editor wasn't set, try to pick a sane default
   return editor unless editor.nil?
 
   # Find Textmate
-  return 'mate' if system "/usr/bin/which -s mate"
+  return 'mate' if which_s "mate"
   # Find # BBEdit / TextWrangler
-  return 'edit' if system "/usr/bin/which -s edit"
+  return 'edit' if which_s "edit"
   # Default to vim
   return '/usr/bin/vim'
 end
@@ -378,6 +383,8 @@ module MacOS extend self
 
   def xcode_version
     @xcode_version ||= begin
+      return "0" unless MACOS
+
       # this shortcut makes xcode_version work for people who don't realise you
       # need to install the CLI tools
       xcode43build = "/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild"
@@ -389,7 +396,7 @@ module MacOS extend self
       # Xcode 4.3 xc* tools hang indefinately if xcode-select path is set thus
       raise if `xcode-select -print-path 2>/dev/null`.chomp == "/"
 
-      raise unless system "/usr/bin/which -s xcodebuild"
+      raise unless which_s "xcodebuild"
       `xcodebuild -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
       raise if $1.nil? or not $?.success?
       $1
@@ -468,9 +475,10 @@ module MacOS extend self
     # http://github.com/mxcl/homebrew/issues/#issue/13
     # http://github.com/mxcl/homebrew/issues/#issue/41
     # http://github.com/mxcl/homebrew/issues/#issue/48
+    return false unless MACOS
 
     %w[port fink].each do |ponk|
-      path = `/usr/bin/which -s #{ponk}`
+      path = `/usr/bin/which #{ponk} 2>/dev/null`
       return ponk unless path.empty?
     end
 

bin/brew

@@ -31,7 +31,7 @@ case HOMEBREW_PREFIX.to_s when '/', '/usr'
   # it may work, but I only see pain this route and don't want to support it
   abort "Cowardly refusing to continue at this prefix: #{HOMEBREW_PREFIX}"
 end
-if MACOS_VERSION < 10.5
+if MACOS and MACOS_VERSION < 10.5
   abort <<-EOABORT.undent
     Homebrew requires Leopard or higher. For Tiger support, see:
     http://github.com/sceaga/homebrew/tree/tiger
@@ -72,7 +72,7 @@ begin
 
   # Add example external commands to PATH before checking.
   ENV['PATH'] += ":#{HOMEBREW_REPOSITORY}/Library/Contributions/cmds"
-  if system "/usr/bin/which -s brew-#{cmd}"
+  if which_s "brew-#{cmd}"
     %w[CACHE CELLAR LIBRARY_PATH PREFIX REPOSITORY].each do |e|
       ENV["HOMEBREW_#{e}"] = Object.const_get "HOMEBREW_#{e}"
     end