.puts -> warn, fixes #429

lib/pry.rb

@@ -163,7 +163,7 @@ if Pry::Helpers::BaseHelpers.jruby?
   begin
     require 'ffi'
   rescue LoadError
-    $stderr.puts "Need to `gem install ffi`"
+    warn "Need to `gem install ffi`"
   end
 end
 
@@ -171,7 +171,7 @@ if Pry::Helpers::BaseHelpers.windows?
   begin
     require 'win32console'
   rescue LoadError
-    $stderr.puts "Need to `gem install win32console`"
+    warn "Need to `gem install win32console`"
     exit 1
   end
 end

lib/pry/default_commands/shell.rb

@@ -32,7 +32,7 @@ class Pry
 
       create_command "save-file", "Export to a file using content from the REPL."  do
         banner <<-USAGE
-          Usage: save-file [OPTIONS] [METH]
+          Usage: save-file [OPTIONS] [FILE]
           Save REPL content to a file.
           e.g: save-file -m my_method -m my_method2 ./hello.rb
           e.g: save-file -i 1..10 ./hello.rb --append

lib/pry/plugins.rb

@@ -9,7 +9,7 @@ class Pry
       end
 
       def method_missing(*args)
-        $stderr.puts "Warning: The plugin '#{@name}' was not found! (no gem found)"
+        warn "Warning: The plugin '#{@name}' was not found! (no gem found)"
       end
     end
 
@@ -45,8 +45,8 @@ class Pry
         begin
           require gem_name if !active?
         rescue LoadError => e
-          $stderr.puts "Warning: The plugin '#{gem_name}' was not found! (gem found but could not be loaded)"
-          $stderr.puts e
+          warn "Warning: The plugin '#{gem_name}' was not found! (gem found but could not be loaded)"
+          warn e
         end
         self.active = true
         self.enabled = true