Advise user if they are not in the right group

install_homebrew.rb

@@ -7,35 +7,50 @@
 # If you do fork, please ensure you add a comment here that explains what the
 # changes are intended to do and how well you tested them.
 #
+# 14th March 2010:
+#   Adapted CodeButler's fork: http://gist.github.com/331512
+#
 
 module Tty extend self
   def blue; bold 34; end
   def white; bold 39; end
   def red; underline 31; end
   def reset; escape 0; end
-  def underline; underline 39; end
   def bold n; escape "1;#{n}" end
   def underline n; escape "4;#{n}" end
   def escape n; "\033[#{n}m" if STDOUT.tty? end
 end
 
-def ohai s
-  puts "#{Tty.blue}==>#{Tty.white} #{s}#{Tty.reset}"
-end
-
-def sudo *params
-  if params.length == 1
-    cmd = "sudo #{params.first}"
-    ohai cmd
-    system cmd
-  else
-    ohai "sudo" + params.map{ |p| p.gsub ' ', '\\ ' } * ' '
-    system "sudo", *params
+class Array
+  def shell_s
+    cp = dup
+    first = cp.shift
+    cp.map{ |arg| arg.gsub " ", "\\ " }.unshift(first) * " "
   end
 end
 
-def opoo warning
-  puts "#{Tty.red}Warning#{Tty.reset}: #{warning}"
+def ohai *args
+  puts "#{Tty.blue}==>#{Tty.white} #{args.shell_s}#{Tty.reset}"
+end
+
+def warn warning
+  puts "#{Tty.red}Warning#{Tty.reset}: #{warning.chomp}"
+end
+
+alias :system_orig :system
+ 
+def system *args
+  abort "Failed during: #{args.shell_s}" unless system_orig *args
+end
+
+def sudo *args
+  args = if args.length > 1
+    args.unshift "sudo"
+  else
+    "sudo #{args}"
+  end
+  ohai *args
+  system *args
 end
 
 def getc  # NOTE only tested on OS X
@@ -47,6 +62,7 @@ end
 
 ####################################################################### script
 abort "/usr/local/.git already exists!" if File.directory? "/usr/local/.git"
+abort "Don't run this as root!" if Process.uid == 0
 
 ohai "This script will install:"
 puts "/usr/local/bin/brew"
@@ -56,11 +72,16 @@ puts "/usr/local/Library/Homebrew/..."
 chmods = %w(bin etc include lib sbin share var . share/locale share/man share/info share/doc share/aclocal).
             map{ |d| "/usr/local/#{d}" }.
             select{ |d| File.directory? d and not File.writable? d }
+chgrps = chmods.reject{ |d| File.stat(d).grpowned? }
 
 unless chmods.empty?
   ohai "The following directories will be made group writable:"
   puts *chmods
 end
+unless chgrps.empty?
+  ohai "The following directories will have their group set to #{Tty.underline 39}staff#{Tty.reset}:"
+  puts *chgrps
+end
 
 puts
 puts "Press enter to continue"
@@ -68,16 +89,19 @@ abort unless getc == 13
 
 if File.directory? "/usr/local"
   sudo "/bin/chmod", "g+w", *chmods unless chmods.empty?
+  # all admin users are in staff
+  sudo "/usr/bin/chgrp", "staff", *chgrps unless chgrps.empty?
 else
   sudo "/bin/mkdir /usr/local"
   sudo "/bin/chmod g+w /usr/local"
+  # the group is set to wheel by default for some reason
+  sudo "/usr/bin/chgrp staff /usr/local"
 end
 
 Dir.chdir "/usr/local" do
-  tarball = "http://github.com/mxcl/homebrew/tarball/master"
-  ohai "Extracting: #{tarball}"
+  ohai "Downloading and Installing Homebrew..."
   # -m to stop tar erroring out if it can't modify the mtime for root owned directories
-  system "/usr/bin/curl -#L #{tarball} | /usr/bin/tar xz -m --strip 1"
+  system "/usr/bin/curl -sfL http://github.com/mxcl/homebrew/tarball/master | /usr/bin/tar xz -m --strip 1"
 end
 
 ohai "Installation successful!"
@@ -88,5 +112,5 @@ if ENV['PATH'].split(':').include? '/usr/local/bin'
   puts "    brew help"
   puts
 else
-  opoo "/usr/local/bin is not in your PATH"
+  warn "/usr/local/bin is not in your PATH"
 end