shangul@ubuntu:~/avr/asm$ sudo avrdude -P /dev/ttyS0 -p m8 -c dasa3 -U flash:w:led0.hex

avrdude: AVR device not responding
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.


avrdude done.  Thank you.

shangul@ubuntu:~/avr/asm$ sudo avrdude -P /dev/ttyS1 -p m8 -c dasa3 -U flash:w:led0.hex
/dev/ttyS1: tcgetattr: Input/output error

avrdude done.  Thank you.

shangul@ubuntu:~/avr/asm$ sudo avrdude -P /dev/ttyS2 -p m8 -c dasa3 -U flash:w:led0.hex
/dev/ttyS2: tcgetattr: Input/output error

avrdude done.  Thank you.