Warn the user of required arguments

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/cmd/cat.rb

@@ -4,6 +4,7 @@ module Homebrew extend self
     # unparsable, if the user wants to cat multiple formula they can call
     # brew cat multiple times.
 
+    raise FormulaUnspecifiedError if ARGV.named.empty?
     cd HOMEBREW_REPOSITORY
     exec "cat", ARGV.formulae.first.path, *ARGV.options_only
   end

Library/Homebrew/cmd/deps.rb

@@ -14,12 +14,14 @@ module Homebrew extend self
         puts "#{f.name}: #{f.deps*' '}"
       end
     elsif ARGV.include? '--tree'
+      raise FormulaUnspecifiedError if ARGV.named.empty?
       ARGV.formulae.each do |f|
         puts f
         recursive_deps_tree(f, 1)
         puts
       end
     else
+      raise FormulaUnspecifiedError if ARGV.named.empty?
       all_deps = ARGV.formulae.map{ |f| ARGV.one? ? f.deps : f.recursive_deps }.intersection
       all_deps.sort! unless ARGV.include? "-n"
       puts all_deps

Library/Homebrew/cmd/fetch.rb

@@ -4,6 +4,8 @@ require 'formula'
 
 module Homebrew extend self
   def fetch
+    raise FormulaUnspecifiedError if ARGV.named.empty?
+
     if ARGV.include? '--deps'
       bucket = []
       ARGV.formulae.each do |f|

Library/Homebrew/cmd/install.rb

@@ -4,6 +4,8 @@ require 'blacklist'
 
 module Homebrew extend self
   def install
+    raise FormulaUnspecifiedError if ARGV.named.empty?
+
     ARGV.named.each do |name|
       msg = blacklisted? name
       raise "No available formula for #{name}\n#{msg}" if msg

Library/Homebrew/cmd/link.rb

@@ -1,5 +1,7 @@
 module Homebrew extend self
   def link
+    raise KegUnspecifiedError if ARGV.named.empty?
+
     ARGV.kegs.each do |keg|
       print "Linking #{keg}... "
       puts if ARGV.verbose?

Library/Homebrew/cmd/options.rb

@@ -11,6 +11,7 @@ def ff
       f.installed? or outdated.include? f.name
     end
   else
+    raise FormulaUnspecifiedError if ARGV.named.empty?
     ARGV.formulae
   end
 end

Library/Homebrew/cmd/test.rb

@@ -1,5 +1,7 @@
 module Homebrew extend self
   def test
+    raise KegUnspecifiedError if ARGV.named.empty?
+
     ARGV.formulae.each do |f|
       # Cannot test uninstalled formulae
       unless f.installed?

Library/Homebrew/cmd/uninstall.rb

@@ -2,6 +2,8 @@ require 'keg'
 
 module Homebrew extend self
   def uninstall
+    raise KegUnspecifiedError if ARGV.named.empty?
+
     unless ARGV.force?
       ARGV.kegs.each do |keg|
         puts "Uninstalling #{keg}..."

Library/Homebrew/cmd/unlink.rb

@@ -1,5 +1,7 @@
 module Homebrew extend self
   def unlink
+    raise FormulaUnspecifiedError if ARGV.named.empty?
+
     ARGV.kegs.each do |keg|
       print "Unlinking #{keg}... "
       puts "#{keg.unlink} links removed"

Library/Homebrew/cmd/uses.rb

@@ -7,7 +7,7 @@ require 'formula'
 
 module Homebrew extend self
   def uses
-    return if ARGV.formulae.empty?
+    raise FormulaUnspecifiedError if ARGV.named.empty?
 
     uses = Formula.all.select do |f|
       ARGV.formulae.all? do |ff|

Library/Homebrew/cmd/versions.rb

@@ -4,6 +4,8 @@ module Homebrew extend self
   def versions
     raise "Please `brew install git` first" unless system "/usr/bin/which -s git"
 
+    raise FormulaUnspecifiedError if ARGV.named.empty?
+
     ARGV.formulae.all? do |f|
       if ARGV.include? '--compact'
         puts f.versions * " "