How to draw an event distribution histogram if each event is one line in the file?

Question

Command line

There is a file with events during the day, where each of them is presented in a simple form:
08/12 11:20:57
08/12 11:20:58 08/12
11:20:58
histogram form.

Any means will do, it's good if linux shell. The task is one-time, the result is perceived by a person. You can write a Python script, but you are interested in the most efficient way to perform such a task, without programming - maybe there are some standard tools for this class of tasks.

Answer 1

awk 'BEGIN{FS=":| " ; prev=-1}{  if (prev != $2) printf("\n%s ",$2); printf("*"); prev=$2; }' file