strace -f -p PID
returns syscalls of the process PID
-eopen filters for open files
-econnect filters for open sockets
sendto(32, „@\4\0\0\20\0\1\0\0\0\0\0\0\0\0\0\5\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0″…, 1088, MSG_NOSIGNAL, NULL, 0
a sendto() syscall, the 32 ist a file descriptor, see /proc/PID/fd/
tbc.