When I run a command like react-native run-ios or react-native start, it launches a new terminal window with the react native compiling process running/watching inside of the new terminal window.
How can I watch for this new process to start? Or find it among running terminal processes? Find the pid, etc.
My task is specific and obscure, but this is more or less exactly what I need to do. Can anyone help?
Checking which PID is used for the port of your react native application should suffice. The standard port for the react-native-cli when running react-native run-ios or react-native start is 8081. For expo it is 19000.
For specifying a custom port (e.g. 9988) use
react-native start --port 9988
When your react native application is running, then you can check the corresponding PID in usage for that port (sudo might be needed at the beginning of the command)
lsof -i -P | grep LISTEN | grep 8081
node 38273 [USER] 31u IPv6 0x2207bcb724ddd40d 0t0 TCP *:8081 (LISTEN)
In this example, the corresponding PID is 38273