How do I I find doubled words in a file

Noticed that mistake in the title? Or missed it? Here's how to catch those in your text files.

perl -nl -e 'print if m/\b(\w+)\s+\1/' filename

Instead if the whole line, you just want to see the line number and the word that is doubled?

perl -nl -e 'print "$. : $1" if m/\b(\w+)\s+\1/' filename

And you want to correct these?

perl -pi -e 's/\b(\w+)\s+\1/\1/g' filename