OpenWRT (from open wireless router) is an open-source project for embedded operating systems based on Linux, primarily used on embedded devices to route network traffic. The main components are Linux, util-linux, musl, and BusyBox. All components have been optimized to be small enough to fit into the limited storage and memory available in home routers.

OpenWrt is configured using a command-line interface (ash shell) or a web interface (LuCI). There are about 3500 optional software packages available for installation via the opkg package management system.

OpenWrt can run on various types of devices, including CPE routers, residential gateways, smartphones, pocket computers (e.g. Ben NanoNote). It is also possible to run OpenWrt on personal computers and laptops, which are most commonly based on the x86 architecture.

In OpenWRT there isn’t a single command that permits to upgrade all ours packages installed, but you can easily do it with this script.

Here a simple command (to run using a connection ssh) that will allow you to update all OpenWRT packages without any effort.

opkg update && opkg list-upgradable | cut -f 1 -d ' ' | xargs -r opkg upgrade

If there are updates they will be updated.
I advise you that this command must be followed only if you are using a stable release of OpenWRT, if it was used on an unstable release or snapshot image it could cause your router to hang.