Off topic:Count columns and delet specific one

Question

[salvatore_d]

Hi All

I've merged a lot of different files with different columns number (12 and 13) and now I'm looking for a way to delete column 4 specifically in those rows with 13 columns. Can you pleas help me?

Example:

at the beggining

1 2 3 4 5 6 7 8 9 10 11 12 13

1 2 3 4 5 6 7 8 9 10 11 12

in the end

1 2 3 5 6 7 8 9 10 11 12 13

1 2 3 4 5 6 7 8 9 10 11 12