Tally counter (Press ESC to exit)

tally-counter

#!/bin/bash

set -euC
# set -o pipefail

declare -A counts

function result () {
  stty "$stty"
  for i in "${!counts[@]}"
  do
    printf "%s\t%d\n" "$i" "${counts[$i]}"
  done | sort
}
trap result EXIT

stty="$(stty -g)"
stty -echo

while read -rn 1 ch
do
  # Press `Esc` to exit
  [ "$ch" = $'\x1b' ] && exit 0

  [ -z "$ch" ] && ch='??'
  counts["$ch"]="$(( ${counts["$ch"]:-0} + 1 ))"
done