Longest line in a file

Question

I\'m looking for a simple way to find the length of the longest line in a file. Ideally, it would be a simple bash shell command instead of a script.

Answer 1

Looks all the answer do not give the line number of the longest line. Following command can give the line number and roughly length:

$ cat -n test.txt | awk '{print "longest_line_number: " $1 " length_with_line_number: " length}' | sort -k4 -nr | head -3
longest_line_number: 3 length_with_line_number: 13
longest_line_number: 4 length_with_line_number: 12
longest_line_number: 2 length_with_line_number: 11