Place this file and your CSV file into the root of your SugarCRM install and you can update data in SugarCRM from a CSV on the command line

update_via_csv.php

<?php

//Use an unlimited amount of memory, we probably shouldn't do this but that is how I roll
ini_set('memory_limit', '-1');

//Our program allows us to skip over rows in the data file and only load a sub-set of rows
if (count($argv) < 3 || ! is_numeric($argv[1]) || ! is_numeric($argv[2])) {
    echo "Usage php -f $argv[0] skip max" . PHP_EOL;
    echo "  skip - number of rows to skip when processing" . PHP_EOL;
    echo "  max - number of rows to import when processing" . PHP_EOL;
    die();
}

$skip = $argv[1];
$max = $argv[2];

//BEGIN STANDARD ITEMS NEEDED TO RUN SUGARCRM FROM THE COMMAND LINE
if (!defined('sugarEntry')) {
    define('sugarEntry', true);
}

chdir(dirname(__FILE__));
define('ENTRY_POINT_TYPE', 'api');
require_once('include/entryPoint.php');

if (empty($current_language)) {
    $current_language = $sugar_config['default_language'];
}

$app_list_strings = return_app_list_strings_language($current_language);
$app_strings = return_application_language($current_language);

//set the $current_user to be the System Administrator, if you want to run as another person use the $current_user->retrieve 
//function to load the appropriate user 
global $current_user;
$current_user = BeanFactory::getBean('Users');
$current_user->getSystemUser();
//END STANDARD ITEMS NEEDED TO RUN SUGARCRM FROM THE COMMAND LINE

echo PHP_EOL;
$column = null;

//open a file handle to a file called dbupdate.csv, you can change this to the appropiate choice
if (($handle = fopen("dbupdate.csv", "r")) !== false) {
    $row = 0;
    $processed = 0;
    while (($data = fgetcsv($handle, 0, ",")) !== false) {
      //row[0] should be the column headers, you'll need to know what is in each column to find data appropriately


        if ($processed >= $max)
            die();

        else {
            if ($row >= $skip && $processed < $max) {
              //$data contains a row of CSV data, use this information to update or find manipulate some data

                $contact = BeanFactory::newBean('Contacts');
                $contactQuery = new SugarQuery();
                $contactQuery->from($contact);
                $contactQuery->where()->equals('last_name', $data[2]);

                foreach ($contact->fetchFromQuery($contactQuery) as $c) {
                    echo "$row | $c->name" . PHP_EOL;
                  //do something
                    $c->save(false);
                    unset($c);
                }
                
                unset($contactQuery);
                unset($contact);

                $processed++;
            }
        }
        $row++;
    }
    fclose($handle);
}