In reply to @lily:lily.flowers
PORT=5173 is not a command

it is just a command line argument

from the docs:

PORT, HOST and SOCKET_PATHpermalink
By default, the server will accept connections on 0.0.0.0 using port 3000. These can be customised with the PORT and HOST environment variables:

HOST=127.0.0.1 PORT=4000 node build
Alternatively, the server can be configured to accept connections on a specified socket path. When this is done using the SOCKET_PATH environment variable, the HOST and PORT environment variables will be disregarded.

SOCKET_PATH=/tmp/socket node build