Strip white space and return first 8 characters

<?php
// http://www.gravityhelp.com/forums/topic/merger-tags-use-part-of-a-tag
// change the 9 in the next line to your form ID
add_action('gform_pre_submission_9', 'custom_company_id');
function custom_company_id($form){
    // change the 5 part of 'input_5' here to the field ID where you want to store the 8 character company name
    // change the 2 part of 'input_2' at the end to the field ID where the full company name was submitted
    // this will strip out all whitespace, then return the first 8 characters
    $_POST['input_5'] = substr(preg_replace('/\s+/', '', rgpost('input_2')), 0, 8);
}