(b:#a;b++/,/a=/:" ";b+#,/a)
b:#a;c:,/a=/:" ";(b;b++/c@&~c&=':c;b+#,/a)
Now to see if I can check the performance.
{+/["\n"=x],+/[<':~x in "\n\r\t "],#x}
{(+/x in"\n\n";+/0>':x in" \n\t\r";#x)}@1:"big.txt"