Sample bash script to get total message count of a Kafka topic.

get_message_count.sh

#!/bin/bash

brokers="localhost:9092"
topic=<YOUR TOPIC>
sum_1=$(/<YOUR_KAFKA_BIN_DIRECTORY>/kafka-run-class kafka.tools.GetOffsetShell --broker-list $brokers --topic $topic --time -1 | grep -e ':[[:digit:]]*:' | awk -F  ":" '{sum += $3} END {print sum}')
sum_2=$(/<YOUR_KAFKA_BIN_DIRECTORY>/kafka-run-class kafka.tools.GetOffsetShell --broker-list $brokers --topic $topic --time -2 | grep -e ':[[:digit:]]*:' | awk -F  ":" '{sum += $3} END {print sum}')
echo "Number of records in topic ${topic}: "$((sum_1 - sum_2))