This started after reading this thread and wondering: what if an ESP8266 behaved less like a single Arduino sketch and more like a tiny persistent UNIX box? https://news.ycombinator.com/item?id=47851630

KernelESP gives the ESP8266 a serial shell, LittleFS filesystem, scripts, pipes, cron, timers, relays, sensor rules, backups, diagnostics, JSON API, web UI, and SMTP email alerts. It is persistent across reboots: config, scripts, relays, rules, cron jobs, profiles, logs, web assets, and help files live in LittleFS.

It supports many familiar UNIX-style commands, including: ls, cd, pwd, cat, echo, touch, rm, mkdir, rmdir, cp, mv, head, tail, grep, find, wc, du, df, mount, stat, basename, dirname, test, uname, hostname, whoami, id, groups, who, w, ps, pgrep, pidof, kill, jobs, dmesg, free, date, which, env, printenv, setenv, source, sh, run, logger, journalctl, sleep, repeat

and ESP/control commands like: wifi, ap, web, relay, timer, crontab, rule, input, sensor, climate, mail, backup, restore, profile, diag, board, health, gpio, read, pwm, adc, i2c, pcf, mcp, ntp, ping, httpget