Update Magento 2 env.php from bash shell script

update_m2_env_script.sh

#!/usr/bin/env bash

set -eu

# Add configs values to env.php
echo "Add configs values programmatically to env.php"
set +H # disable history expansion
PHP_CODE=$(cat <<'PHP_CODE'
<?php
$existing_env = include("app/etc/env.php");
$new_env = 
    array (
      'session' => 
      array (
        'save' => 'redis',
        'redis' => 
        array (
          'host' => '127.0.0.1',
          'port' => '6380',
          'password' => '',
          'timeout' => '2.5',
          'persistent_identifier' => '',
          'database' => '0',
          'compression_threshold' => '2048',
          'compression_library' => 'gzip',
          'log_level' => '1',
          'max_concurrency' => '6',
          'break_after_frontend' => '5',
          'break_after_adminhtml' => '30',
          'first_lifetime' => '600',
          'bot_first_lifetime' => '60',
          'bot_lifetime' => '7200',
          'disable_locking' => '0',
          'min_lifetime' => '60',
          'max_lifetime' => '2592000',
        ),
      ),
      'cache' => 
      array (
        'frontend' => 
        array (
          'default' => 
          array (
            'backend' => 'Cm_Cache_Backend_Redis',
            'backend_options' => 
            array (
              'server' => '127.0.0.1',
              'database' => '0',
              'port' => '6379',
              'password' => '',
            ),
          ),
        ),
      ),
    )
  ;
$merged_env = array_merge(
  $existing_env,
  $new_env
);
$combined_env = var_export($merged_env, true);
echo "<?php
return " . $combined_env . ";
";
PHP_CODE
)
set -H # re-enable history expansion
#cat ${MAGENTO_ROOT_DIR}/app/etc/env.php

# Get the new file contents in a bash variable before writing to file
# If anything breaks during merging the contents it will not write over the env.php
# This also prevents the env.php from getting overwritten until we have extracted
# all of the existing contents and have merged everything together
NEW_ENV=$(echo "${PHP_CODE}" | php)

#echo "${NEW_ENV}"
# Overwrite env.php with combined configs
echo "${NEW_ENV}" > ${MAGENTO_ROOT_DIR}/app/etc/env.php
echo "Finished adding configs values programmatically to env.php"