This will replace strings in a file.

replace_string.rb

#!/usr/bin/ruby -w  
 
def replace_ref(file, fileindx, &directive)
    old_stdout = $stdout
    argf = ARGF.clone
 
    argf.argv.replace [file]
    argf.inplace_mode = fileindx
    argf.each_line() { |line|
        yield line
    }
 
    $stdout = old_stdout
end
 
 
File.open('files').each {
    |i|
    puts i
    begin
        replace_ref i.chomp, '.bk' do |line|
        puts i + " Is being changed..."
        line = line.gsub(/\/common\/js\/extern\/omniture\/s_code.js/,"/js/extern/omniture/s_code.js")
        print line
        end
    rescue
        puts i.chomp + " Does not exist...".upcase
    end
 
}