```ruby
#
# Cookbook Name:: line
# Library:: default
#
# Author:: Sean OMeara <someara@opscode.com>                                  
# Copyright 2012-2013, Opscode, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#    

def escape_string(string)
  pattern = /(\+|\'|\"|\.|\*|\/|\-|\\|\(|\)|\{|\})/
  string.gsub(pattern){|match|"\\" + match}
end
```

Add $ and ^ to list of characters to escape in regex.
user
```ruby
#
# Cookbook Name:: line
# Library:: default
#
# Author:: Sean OMeara <someara@opscode.com>                                  
# Copyright 2012-2013, Opscode, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#    

def escape_string(string)
  pattern = /(\+|\'|\"|\.|\*|\/|\-|\\|\(|\)|\{|\}|\^|\$)/
  string.gsub(pattern){|match|"\\" + match}
end
```
assistant