private static Set<PosixFilePermission> parsePosixFilePermissions(final String filePermissions) {
        if (filePermissions == null || filePermissions.isEmpty()) {
            return null;
        }

        try {
            return PosixFilePermissions.fromString(filePermissions);
        } catch (IllegalArgumentException e) {
            LOGGER.debug("Invalid file permissions format: '" + filePermissions + "'");
            return null;
        }
    }
Parses a POSIX-style file permission string like "rwxr--r--"
stroom-pipeline/src/main/java/stroom/pipeline/writer/RollingFileAppender.java