Hi

Let's say I'd want to modify each line of a file. Here's the dummy
data:

  $ cat data.txt
  first foo
  second foo
  third foo
  $

This works:

  $ ruby -ne '$_ =~ /(\S+)\s+(\S+)/;puts "#{$2} #{$1}"' data.txt
  foo first
  foo second
  foo third
  $

I don't really need to achieve that modification. Instead I'd like to
understand why the following version one doesn't work:

  $ ruby -pe 'sub(/(\S+)\s+(\S+)/,"#{$2} #{$1}")' data.txt

  foo first
  foo second
  $

TIA,
Tobi