networking

Networking, transfer, and connectivity

curl

Tested curl examples: GET/POST/PUT/DELETE, headers, auth, cookies, uploads, redirects, retries, and scripting.
ss

Tested ss examples: listing listening sockets, finding the process holding a port, filtering by state and address, and reading the queue columns.
ssh

Tested ssh examples: key-based auth, the config file, host key verification, port forwarding, multiplexing, and reading a failed connection.
wget

Tested wget examples: downloading, resuming, retries, authentication, recursive mirroring, and scripting with exit codes.
Copy files between two machines over SSH

Transfer a file or directory tree between two machines with scp or rsync, and resume an interrupted transfer without starting over.
Find and kill whatever is using a port

Identify the process bound to a TCP port that's refusing to let a service start, then stop it.