Script for moving offset from one cluster to another

offsets_mover.sh

#!/usr/bin/env bash

# example usage: ./offsets_mover.sh localhost:9092 client.1.properties localhost:9093 client.2.properties

# get bootstrap servers from args
BOOTSTRAP_SERVER=$1

# get properties file location from args
PROPERTIES_FILE=$2

# get new bootstrap servers from args
NEW_BOOTSTRAP_SERVER=$3

# get new properties file location from args
NEW_PROPERTIES_FILE=$4

# get list of all consumer groups
groups=$(kafka-consumer-groups --bootstrap-server $BOOTSTRAP_SERVER --command-config $PROPERTIES_FILE --all-groups --list)

# loop through all consumer groups
for group in $groups
do
   # get group topic partition and current offset in format new-group pageviews 0 7825
   kafka-consumer-groups --bootstrap-server $BOOTSTRAP_SERVER --command-config $PROPERTIES_FILE --group $group --describe | awk '{print $1,$2,$3,$4}' | tail -n +3 > tmp.txt

    # read tmp.txt file line by line and split each line into array
    while IFS= read -r line
    do
        # split line into array
        arr=($line)
        # print group topic partition and current offset
        echo "kafka-consumer-groups --bootstrap-server $NEW_BOOTSTRAP_SERVER --command-config $NEW_PROPERTIES_FILE --group ${arr[0]} --reset-offsets --to-offset ${arr[3]} --topic ${arr[1]}:${arr[2]} --dry-run"
    done < tmp.txt
done

In line 32, do we have to modify the --dry-run to be able to reset the offsets in the new cluster?

yes correct, you usually need to do a dry-run first.