print out file wiht numbers of line

#!/usr/bin/ruby
# put out file wiht numbers out
#

file=ARGV[0] 

begin
  lines=File.open(file, "r").readlines
  format="%0#{lines.size.to_s.size}d"
  lines.each_with_index { |l, i|
    puts "#{sprintf(format, i+1)}: #{l}"
  }
rescue
  puts "no file???   or errors"
end