Reopen shell connection

Long shot here is it possible to reconnect to existing process launched by the shell command.

I have a console app that runs a timer and I get the data with readall
Is it possible reconnect after sh.close?

I would like to run something like sh.execute /pid 1234 where 1234 is the pid of the console app described above to have access to readall again

No. You should subclass shell, implement the DataAvailable event and then set the mode to asynchronous. Whenever the app has results to send you, the DataAvailable event will fire.