Ruby: Searching a regular expression across multiple files in multiple directories

Question

Please forgive my ignorance, I am new to Ruby.

I know how to search a string, or even a single file with a regular expression:

str = File.read('example.txt')
match = str.scan(/[0-9A-Za-z]{8,8}/)

puts match[1]

I know how to search for a static phrase in multiple files and directories

pattern = "hello"

Dir.glob('/home/bob/**/*').each do |file|
    next unless File.file?(file)
        File.open(file) do |f|
            f.each_line do |line|
                puts "#{pattern}" if line.include?(pattern)
        end
    end
end

I can not figure out how to use my regexp against multiple files and directories. Any and all help is much appreciated.

Answer 1

Well, you're quite close. First make pattern a Regexp object:

pattern = /hello/

Or if you are trying to make a Regexp from a String (like passed in on the command line), you might try:

pattern = Regexp.new("hello")
# or use first argument for regexp
pattern = Regexp.new(ARGV[0])

Now when you are searching, line is a String. You can use match or scan to get the results of it matching against your pattern.

f.each_line do |line|
  if line.match(pattern)
    puts $0
  end
  # or
  if !(match_data = line.match(pattern)).nil?
    puts match_data[0]
  end
  # or to see multiple matches
  unless (matches = line.scan(pattern)).empty?
    p matches
  end
end