What is atinout?
Atinout is a program that reads a list of AT commands. It sends those commands one by one to the modem, waiting for the final result code for the currently executing command before continuing with the next command in the list. The output from the commands is captured.
$ echo AT > input.txt $ atinout input.txt /dev/ttyS0 output.txt $ cat output.txt AT OK $
$ echo AT | atinout - /dev/ttyS0 - AT OK $
More examples on the screenshots page.