tinymce-button-filter.php

<?php

add_filter("mce_buttons", "tinymce_editor_buttons", 99); //targets the first line
add_filter("mce_buttons_2", "tinymce_editor_buttons2", 99); //targets the first line

function tinymce_editor_buttons() {
    return array(
        "bold",
        "italic",
        "strikethrough",
        "bullist",
        "numlist",
        'blockquote',
        "separator",
        'alignleft',
        'aligncenter',
        'alignright',
        'link',
        'unlink',
        'wp_adv'
    );
}
function tinymce_editor_buttons2() {
    return array(
        "fontsizeselect",
        "formatselect",
        'underline',
        'alignjustify',
        'forecolor',
        'pastetext',
        'removeformat',
    );

}