Easy uploading of new versions is a good point, and I agree that the likely security holes in the bash script are less of a concern if only trusted users have access to it. However, about 99% of embedded devices lack an MMU, much less 50K of storage, which makes it hard to run Unix shells on them.
Busybox runs MMU-less and has ash built in. It also has a web server! It can be a little chonky but you can remove unneeded components. Things like wireless routers and other devices that have a decent amount of storage are a good platform for it
Yeah, a lot of wireless routers would have no trouble. A lot of them do in fact have MMUs. I wonder if you could get Busybox running on an ESP32? Probably not most 8051s, though, or AVR8s.
Looks like the ESP32-S3 model works with modern Linux (it's so bloated compared to the old 2.0/2.2/2.4 branches...)
The other option seems to be Apache NuttX as an RTOS (runs on all ESP32), and then Busybox w/hush or Toybox w/toysh. The more shell features you need, the more space it's gonna take, but technically 64 kB flash is possible.
