How to extract lines containing blank in a specific column with Linux command

Question

Example:

aa\tab\tac\tad\tae
ba\tbb\tbc
ca\tcb\tcc
da\tdb\tdc\tdd

Expected output:

ba\tbb\tbc
ca\tcb\tcc

I want to extract lines containing blank in a 4th column with linux command. If you know the command, could you let me know it?

Answer 1

Using awk

$ awk -F"\\" '{if($4=="") print}' input_file
ba\tbb\tbc
ca\tcb\tcc