On Mon, 2010-03-15 at 12:32 -0600, Dave Smith wrote: > Dave Smith wrote: > > That's what I was looking for. I didn't escape the 'x' when I tried > > initially. > > Actually, that appears to not work as I expected. The first problem is > that echo needs -n to *not* print a newline character, which would not > normally be a problem (but for purity's sake I added -n). The second > problem is that the last byte (0x00) does not get written to the device, > I assume because echo interprets it as a null-termination character. > After it failed to turn on the relay, here's what I did to investigate: > > echo -n $'\xff\x01\x00' > /tmp/foo.txt > hexdump -C /tmp/foo.txt > 0000000 ff 01 > > And ls -l confirms that the file is only 2 bytes in size (not 3 as I > expected). Is it not possible to write a 0x00 byte as the final byte > using echo? > > Any ideas why this happens?
Because echo is merely processing its argv and the '\0' is seen as terminating the arg, not part of the arg. -- "XML is like violence: if it doesn't solve your problem, you aren't using enough of it." - Chris Maden /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
