diff --git a/.gitignore b/.gitignore
index 9c38e974..d0b8649e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ doc/
 pkg/
 coverage/
 .yardoc/
+/tags
diff --git a/lib/pry/command_processor.rb b/lib/pry/command_processor.rb
index bb273823..3679f3ff 100644
--- a/lib/pry/command_processor.rb
+++ b/lib/pry/command_processor.rb
@@ -55,7 +55,10 @@ class Pry
     def command_matched(val, target)
       _, cmd_data = commands.commands.find do |name, data|
 
-        command_regex = /^#{convert_to_regex(name)}(?!\S)/
+        prefix = Regexp.escape(Pry.config.command_prefix)
+        prefix = "(?:#{prefix})?" unless data.options[:require_prefix]
+
+        command_regex = /^#{prefix}#{convert_to_regex(name)}(?!\S)/
 
         if data.options[:interpolate]
           # If interpolation fails then the command cannot be matched,
diff --git a/lib/pry/command_set.rb b/lib/pry/command_set.rb
index 3b185382..1c30299e 100644
--- a/lib/pry/command_set.rb
+++ b/lib/pry/command_set.rb
@@ -105,7 +105,8 @@ class Pry
         :keep_retval => false,
         :argument_required => false,
         :interpolate => true,
-        :listing => name
+        :listing => name,
+        :require_prefix => true
       }.merge!(options)
 
       unless command_dependencies_met? options
diff --git a/lib/pry/config.rb b/lib/pry/config.rb
index f9b88fa2..9f0e93d6 100644
--- a/lib/pry/config.rb
+++ b/lib/pry/config.rb
@@ -57,6 +57,11 @@ class Pry
     # @return [String, #call]
     attr_accessor :editor
 
+    # A string that must precede all Pry commands (e.g., if command_prefix is
+    # set to "%", the "cd" command must be invoked as "%cd").
+    # @return [String]
+    attr_accessor :command_prefix
+
     # @return [Boolean] Toggle Pry color on and off.
     attr_accessor :color
 
diff --git a/lib/pry/default_commands/shell.rb b/lib/pry/default_commands/shell.rb
index 371fd970..7b31b49c 100644
--- a/lib/pry/default_commands/shell.rb
+++ b/lib/pry/default_commands/shell.rb
@@ -3,7 +3,7 @@ class Pry
 
     Shell = Pry::CommandSet.new do
 
-      command(/\.(.*)/, "All text following a '.' is forwarded to the shell.", :listing => ".<shell command>") do |cmd|
+      command(/\.(.*)/, "All text following a '.' is forwarded to the shell.", :listing => ".<shell command>", :require_prefix => false) do |cmd|
         if cmd =~ /^cd\s+(.+)/i
           dest = $1
           begin
diff --git a/lib/pry/pry_class.rb b/lib/pry/pry_class.rb
index d3754dae..a7d669e3 100644
--- a/lib/pry/pry_class.rb
+++ b/lib/pry/pry_class.rb
@@ -199,6 +199,7 @@ class Pry
     config.editor = default_editor_for_platform
     config.should_load_rc = true
     config.disable_auto_reload = false
+    config.command_prefix = ""
 
     config.plugins ||= OpenStruct.new
     config.plugins.enabled = true
diff --git a/test/test_command_processor.rb b/test/test_command_processor.rb
index d277f49d..02f40821 100644
--- a/test/test_command_processor.rb
+++ b/test/test_command_processor.rb
@@ -93,6 +93,57 @@ describe "Pry::CommandProcessor" do
     pos.should == command.name.length
   end
 
+  it 'should correctly match a command preceded by the command_prefix if one is defined' do
+    Pry.config.command_prefix = "%"
+
+    @pry.commands.command("test-command") {}
+    command, captures, pos = @command_processor.command_matched "%test-command hello", binding
+
+    command.name.should == "test-command"
+    captures.should == []
+    pos.should == "test-command".length + "%".length
+
+    Pry.config.command_prefix = ''
+  end
+
+  it 'should not match a command not preceded by the command_prefix if one is defined' do
+    Pry.config.command_prefix = "%"
+
+    @pry.commands.command("test-command") {}
+    command, captures, pos = @command_processor.command_matched "test-command hello", binding
+
+    command.should == nil
+    captures.should == nil
+
+    Pry.config.command_prefix = ''
+  end
+
+  it 'should match a command preceded by the command_prefix when :require_prefix => false' do
+    Pry.config.command_prefix = "%"
+
+    @pry.commands.command("test-command", "", :require_prefix => false) {}
+    command, captures, pos = @command_processor.command_matched "%test-command hello", binding
+
+    command.name.should == "test-command"
+    captures.should == []
+    pos.should == "test-command".length + "%".length
+
+    Pry.config.command_prefix = ''
+  end
+
+  it 'should match a command not preceded by the command_prefix when :require_prefix => false' do
+    Pry.config.command_prefix = "%"
+
+    @pry.commands.command("test-command", "", :require_prefix => false) {}
+    command, captures, pos = @command_processor.command_matched "test-command hello", binding
+
+    command.name.should == "test-command"
+    captures.should == []
+    pos.should == "test-command".length
+
+    Pry.config.command_prefix = ''
+  end
+
   it 'should correctly match a regex command with spaces in its name' do
     regex_command_name = /test\s+(.+)\s+command/
     @pry.commands.command(regex_command_name) {}
@@ -201,5 +252,4 @@ describe "Pry::CommandProcessor" do
     # you'll cause yourself incredible confusion
     lambda { @command_processor.command_matched('boast #{c}', binding) }.should.not.raise NameError
   end
-
 end