Hi @laszloballa , BR full script is as follows:

See  var originalContentsInFile = Packages.java.lang.String(bytesInFile);

(function executeRule(current, previous /*null when async*/ ) {
    var comment = current.variables.u_comment.toString(); // get the value of Comment from catalog item
    var ritmNumber = current.number; // get the value of RITM number

    // get the attachment record from the current RITM
    var attachmentGR = new GlideRecord('sys_attachment');
    attachmentGR.addQuery('table_name', 'sc_req_item');
    attachmentGR.addQuery('table_sys_id', current.sys_id);
    attachmentGR.addQuery('file_name', 'CONTAINS', '.csv');
    attachmentGR.query();
    if (attachmentGR.next()) {
        var gsa = new GlideSysAttachment();
        var tableName = attachmentGR.getValue('table_name');
        var sysId = attachmentGR.getValue('table_sys_id');
        var bytesInFile = gsa.getBytes(tableName, sysId);
        var originalContentsInFile = Packages.java.lang.String(bytesInFile);
        originalContentsInFile = String(originalContentsInFile);
        var rows = originalContentsInFile.split('\n');
        var columnA = [];
        for (var i = 1; i < rows.length; i++) { // start from index 1 to skip the header row
            var columns = rows[i].split(',');
            columnA.push(columns[0]);
        }
        var concatenatedDeviceID = columnA.join(',');

        // gs.print("Data in Column A concatenatedDeviceID : " + concatenatedDeviceID);

        var ci = new GlideRecord('cmdb_ci_hardware');
        ci.addQuery('serial_number', 'IN', concatenatedDeviceID.split(","));
        ci.query();
        //    var count = ci.getRowCount();
        //    gs.info('Found ' + count + ' hardware records with serial numbers ' + concatenatedDeviceID);
        while (ci.next()) {
            var workNotes = ci.getValue('u_work_notes'); // get the existing work_notes value
            var newWorkNotes = "RITM number: " + ritmNumber;
            if (comment) {
                newWorkNotes += "\nComment: " + comment; // add the comment to the work_notes value if provided
            }
            // gs.print("work_notes : " + newWorkNotes);
            // set newNotes as the journal entry for u_work_notes
            var field = ci.u_work_notes;
            field.setJournalEntry(newWorkNotes);
            ci.update(); // save the changes
        }
        //    gs.print("Records Updated in cmdb_ci_hardware.");
    } //else {
    //  gs.print("No matching records found in cmdb_ci_hardware.");
    // }
})(current, previous);