How can I detect DOS line breaks in a file?

Question

I have a bunch of files. Some are Unix line endings, many are DOS. I\'d like to test each file to see if if is dos formatted, before I switch the line endings.

How

Answer 1

Using grep & bash:

grep -c -m 1 $'\r$' file

echo $'\r\n\r\n' | grep -c $'\r$'     # test

echo $'\r\n\r\n' | grep -c -m 1 $'\r$'