Startup flags and environment variables

The behaviour of Cadabra can be tuned at startup by using startup flags as well as environment variables. Most of these are for debugging purposes and should normally left unchanged from their defaults.

Environment variables

Each of the following environment variables can be set to a non-empty value to trigger the behaviour listed in the right-hand column. CADABRA_SHOW_RECV & \text{Show all messages which the notebook receives from the kernel on stdout.}\\ CADABRA_SHOW_SENT & \text{Show all messages which the notebook sends to the kernel on stdout.}\\ CADABRA_NO_UNICODE & \text{Do not use unicode when displaying expressions in the terminal.}\\ CADABRA_LOG_OUTPUT & \text{Windows only: store stdout and stderr in a log file.}

Startup flags

The notebook interface normally starts a new Cadabra kernel (cadabra-server) when it opens, but it is possible to start the kernel manually and then instruct the notebook interface to connect to that already running kernel. The following flags achieve that: --server-port, -s & \text{Connect to a running server on a given port.} \\ --server-ip-address, -a & \text{Connect to a running server on the given IP address.}\\ --token, -t & \text{Use the given authentication token to connect to the server.}

The server itself can be started as cadabra-server [port] [exit-on-disconnect], where port is the port on which the server will listen (use $0$ to let it pick a random free port) and exit-on-disconnect (if non-empty) instructs the server to exit as soon as the notebook disconnects.

Finally the command-line client cadabra2 accepts a single flag -d which will run Cadabra under control of the debugger.