cheat sheets.

Overview
========
grep searches for lines matching a pattern.

$ grep [OPTION]... PATTERN [FILE] ...

PATTERN can be a normal string or a regular expression. For more on regular
expressions see:
$ cheat regexp

Get full help:
$ grep --help

Basic Usage
===========
$ grep index *.rb
admin_controller.rb:  def index
store_controller.rb:  def index
store_controller.rb:    redirect_to_index 'Invalid product'
store_controller.rb:      redirect_to_index "Your cart is currently empty."


Useful Options
==============
-h:   suppress file names in output
-w:   restrict search to whole words only
-c:   displays count of matching lines in each file, not the lines themselves
      (note this is not the same as $ grep index *.rb | wc -l)
-i:   ignore case
-l:   list only file names containing matching lines
-n:   precede each line with the line number where it was found
-v:   display all lines NOT matching pattern
-C:   Display NUM lines of context either side of matches
-e pattern: 
      Search for a pattern. Can use multiple times on a line
-r:   Search recursively from the current or specificed directory
  --include=pattern:
      Only search in file names matching pattern
  --exclude=pattern:
      Do not search in file names matching pattern

Examples
========

Recursive search, multiple patterns:

$ grep -r --include=*.rb -e "TagsHelper" -e "tags_helper" .
./app/models/foo.rb:  include TagsHelper
./app/models/bar.rb:  include TagsHelper
./vendor/plugins/acts_as_taggable_on_steroids/lib/tags_helper.rb:module
TagsHelper
./vendor/plugins/acts_as_taggable_on_steroids/test/abstract_unit.rb:require_depen
ency File.dirname(__FILE__) + '/../lib/tags_helper'
./vendor/plugins/acts_as_taggable_on_steroids/test/tags_helper_test.rb:class
TagsHelperTest < Test::Unit::TestCase
./vendor/plugins/acts_as_taggable_on_steroids/test/tags_helper_test.rb:  include
TagsHelper