can‘t open /dev/ttyS0: No such file or directory can‘t open /dev/ttyS0: No such file or directory can‘t open /dev/ttyS0: No such file or directory can‘t open /dev/ttyS0: No such file or directory can‘t open /dev/ttyS0: No such file or directory can‘t open /dev/null: No such file or directory can‘t open /dev/null: No such file or directory can‘t open /dev/null: No such file or directory can‘t open /dev/null: No such file or directory can‘t open /dev/null: No such file or directory
