Netmiko, pexpect, tmux, or expect: choosing the right CLI automation tool

Automating interactive command-line sessions involves a common pattern — open a pseudo-terminal, send input, and wait for an expected response — but picking the right existing tool saves significant time. Netmiko is a Python library built on Paramiko, designed specifically for network devices like switches and routers, handling vendor-specific quirks automatically. For non-network interactive programs in Python, pexpect offers a general-purpose alternative, while the original expect(1) tool serves dependency-free or minimal environments. tmux, though primarily a terminal multiplexer, can also be used as an automation surface via its send-keys and capture-pane commands. Ansible's network_cli rounds out the options for teams preferring a declarative, idempotent approach to network device configuration over raw scripting.