Sometimes you want to count the number of characters or columns in a file.
awk 'length>max{max=length}END{print max}' filename.txt
For extraordinarily long or wide data sets you may want to consider the following:
head -n 10 | awk 'length>max{max=length}END{print max}'
OR
tail -n 10 | awk 'length>max{max=length}END{print max}'