$ echo -n $'atcg\r\nhello\r\n' > ATCG_FILE # this is our test file

$ perl -mcharnames -e 'my $s = join "", <>; printf "%s: %d\n",  charnames::viacode(ord $1), pos($s) while $s =~ m/([^atcg])/ig' ATCG_FILE

CARRIAGE RETURN: 5
LINE FEED: 6
LATIN SMALL LETTER H: 7
LATIN SMALL LETTER E: 8
LATIN SMALL LETTER L: 9
LATIN SMALL LETTER L: 10
LATIN SMALL LETTER O: 11
CARRIAGE RETURN: 12
LINE FEED: 13