https://mareksuppa.com/til/bash-dev-tcp-http-without-curl/
Marek Šuppa
Making HTTP requests from a container that has no curl, using bash /dev/tcp
Minimal container images often ship without curl, wget, or any HTTP client at all. Bash can open a TCP socket through /dev/tcp, which is enough to write a tiny HTTP/1.1 request by hand for quick checks.
