Ticket #16031: 16031-plugin-example.php

<?php
// Add the button to the bulk action dropdown.
add_action( 'bulk_actions-edit-post', function($actions) {
        $actions['glerf'] = 'Glerf';
        return $actions;
});

// Add a form submission handler.
add_action( 'handle_bulk_actions-edit-post', function($action) {
        if ( $action !== 'glerf') {
                return;
        }
        // do something productive here
});

// Add a filter on the "sendback" URL, to give the next List Table load statefulness
// about what happened. Then we could display an admin message to tell the user
// about what happened here.
add_filter( 'after_handle_bulk_actions_sendback_link-edit-post', function($sendback, $action) {
        if ( $action !== 'glerf' ) {
                return $sendback;
        }
        $sendback = add_query_arg('glerfed', 1, $sendback);
        return $sendback;
}, 10, 2);