$ for i in test_data test_data_Q check_lf check_crlf; do head -1 $i | cat -vet; done
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX$
QueryXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX$
qwerty$
qwerty^M$