credit: https://community.checkpoint.com/t5/user/viewprofilepage/user-id/15143

script_change_expiration_of_users.sh

#!/bin/bash
# Created by tvobruba
# version 001
# script is checking and changing expiration date for all internal users in CP MGMT database
# usage: chmod 700 && ./script.sh

date=1609459162000 #setup checked date in ms epoch time - 2020-12-31 16:45
new_date="2035-01-01" #setup new desired date in ISO format

# export list of users to file
mgmt_cli -r true show users --format json |jq '.objects[].name' > list.txt


echo "Checking expiration time of all users..."
echo -e "";
for user in `cat ./list.txt`; do

expiration=`mgmt_cli -r true show user name $user --format json |jq '."expiration-date".posix'`
echo User: $user, $expiration
echo ""

if [ $date \> $expiration ];
then
    echo "$user will expire before 31.12.2020 23:55";
        echo "Setting new expiration..."
        echo ""
        mgmt_cli -r true  set user name $user  expiration-date "$new_date"  --format json
else
    echo "$user will expire not before: `date -d @$(  echo "($expiration + 500) / 1000" | bc)`";
fi;

done

rm -f ./list.txt