So, what you want to do is to store the result of the match
method, you can then get the actual matched word out of that, ie.
if m = line.match( /\b#{input}\b/i )
puts "#{m[0]} was found in the file."
# ... etc.
end
Update
Btw, you didn't ask - but I would use scan
in this case, so that I got an array of the matched words on each line (for when there's more than one match on the same line), something like this:
if m = line.scan( /\b#{input}\b/i )
puts "Matches found on line #{f.lineno}: #{m.join(', ')}"
# ... etc.
end