./1/dos1.txt: ASCII text, with CRLF line terminators
./2/dos2.txt: ASCII text, with CRLF line terminators
./dos.txt: ASCII text, with CRLF line terminators
# list files containing dos line endings (CRLF)
cr="$(printf "\r")" # alternative to ctrl-V ctrl-M
grep -Ilsr "${cr}$" .
grep -Ilsr $'\r$' . # yet another & even shorter alternative