Why not just `nc` (netcat) with auth? It’s janky but fits the "simple proxy with auth linux command" ask.
```
mkfifo pipe
nc -l -p 8080 < pipe | nc target.com 80 > pipe
```
Add auth with `htpasswd` if you’re feeling fancy. Not for production, but for testing? Sure.
```
mkfifo pipe
nc -l -p 8080 < pipe | nc target.com 80 > pipe
```
Add auth with `htpasswd` if you’re feeling fancy. Not for production, but for testing? Sure.