steve jenkin | 24 Nov 03:56 2014

[clug] using 'dd' in a pipeline

I’ve been looking at deliberate MD5 collisions and went to write a simple script based on ‘dd’, only
to fall flat on my face - detecting ‘end of file’ from STDIN.

‘dd’ doesn’t consider EOF as an error and returns “success”.

I could use dd’s “iseek”, but that ties me to named files in the file system :(
I’d prefer to use a pipeline - current script below, but it requires I first know the size of the file,
exactly the same issue as ‘iseek’.

One option is to catch the output of ‘dd’ in a temporary file, then test for its size, ending when the temp
file is zero length.

I tried using the bash ‘read’ with "-n 0”, but that reads an entire line [not good for a binary file]
‘IFS=“” read -r -n 1’ runs, but consumes a byte of the input and discards binary ‘\0’ bytes :(

The stat() and read() system calls either don’t report EOF, or return zero-length at EOF.

I could test if a program that does a read() of zero-length, then uses ‘select’ with a short timeout,
would reliably detect EOF on STDIN if it was a pipe or file.
It doesn’t seem reliable & portable to me, but it may be.

ioctl() and fcntl() didn’t seem to have

Anyone got ideas that I can use in a shell script? I’d prefer not to have to write code :)
There may already be extended versions of ‘dd’ that do this (haven’t checked these: dc3dd dcfldd
dd_rescue ddd)

Or suggestion on existing tools or how to implement a simple test for EOF on STDIN (pipe or file) in PERL, PHP
or other scripting languages.

(Continue reading)

Bryan Kilgallin | 23 Nov 19:22 2014

[clug] Full Circle

Issue three got excited about 3D representation eye candy.

And there were articles on desktop layout, scrawling notes, desktop 
publishing, photography, music, multimedia encoders and video tutorials.

Users described their PC, desktop, and Ubuntu experience.

An Apple notebook was praised. And dual boot was discussed.

There was an exposition on Xubuntu. And a whine about American software 



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Paul Wayper | 23 Nov 12:30 2014

[clug] Next meeting and more

Hi all,

I've decided to step down from running the CLUG and PSIG.

I've been doing this job for many years now, and it's been increasingly
difficult for me to do well.  In part this is just because my focus has
changed, but mostly it's just because I've been doing it now for long enough
that the continual struggle to get another speaker or to organise a
discussion topic when we don't have one has made me tired and
unenthusiastic.  And CLUG deserves better than that.

So if you're interested in seeing CLUG meetings continue, in any form,
please come along to the meeting this Thursday to discuss what happens next.

Hope this helps,

Bryan Kilgallin | 20 Nov 12:48 2014

[clug] Full Circle

I just finished reading the old second issue. And I liked the articles 
on distro, installation and applications. But not the list of poor and 
unnecessary widgets!



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Bryan Kilgallin | 17 Nov 16:53 2014

[clug] CPU speed in MHz

On my PC, "cat /proc/cpuinfo" lists the CPU speed, as follows.

cpu MHz        : 2793.242

But using the same command on my mobile phone does not yield that item.
Rather I got the following list. How might one calculate an equivalent 
to the above,
given this following information?

Processor    : ARM920T rev 0 (v4l)
BogoMIPS    : 199.47
Features    : swp half thumb
CPU implementer    : 0x41
CPU architecture: 4T
CPU variant    : 0x1
CPU part    : 0x920
CPU revision    : 0
Cache type    : write-back
Cache clean    : cp15 c7 ops
Cache lockdown    : format A
Cache format    : Harvard
I size        : 16384
I assoc        : 64
I line length    : 32
I sets        : 8
D size        : 16384
D assoc        : 64
D line length    : 32
D sets        : 8

(Continue reading)

Bryan Kilgallin | 15 Nov 08:27 2014

[clug] Desktop commandline & remote embedded device

My Openmoko phone has restricted busybox Linux software. Whereas my 
desktop PC has a much larger suite of commandline programs.
I wanted to use the Desktop PC's commandline programs to interrogate the 
phone. But I didn't know how to tell the former to look at the latter, 
which ws connected via SSH.

Specifically I tried using lscpu. The error message told me that it was 
looking for /proc/cpuinfo. So I used the phone to vi that file.

The commandline connection method is as follows.
ssh root@...

How can I instruct my PC's commandline programs (lscpu in the above 
example) to query the phone instead of the PC?



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Paul Wayper | 15 Nov 04:46 2014

[clug] Serial communications between Atmel processors

Hi all,

I've got a fairly specific programming question - if I'd thought about it I
could have had the programming SIG to talk about it, but my brain was too
slow for that.

I'm trying to get two (or more) ATTiny85s to talk to eachother.  I'm using
the standard Arduino environment and their SoftwareSerial library.  The code
is fairly simple - it sets up the serial connection and starts in state '1'.
 If the serial port has received something, if it's a '1' then it sends a '2',
otherwise it sends a '1'.  Then if the state is '1' it turns on LED 1 and
turns off LED 2 and vice versa for state '2'.

The basic circuit is each ATTiny has PB0 and PB1 (pins 5 and 6) connected to
two LEDS; PB2 is RX and PB3 is TX (pins 7 and 3).  They use a common ground
and VCC (which is a Lithium polymer battery, currently at about 3.8V) and
the TX of one ATTiny is connected to the RX of the other.  The code is at:

The problem is that it starts up and both boards turn LED 1 on and 2 off,
and stay like that permanently.

I've put a delay between reading the character off the available port and
sending the response, but that doesn't change anything.  I started with snd
and rcv instantiated within the loop, but they're now global, and I started
with only case 1 and the default and now I have case 1, 2, and default being
different (as you can see in the code).  None of those changes have changed
the behaviour.
(Continue reading)

Bryan Kilgallin | 14 Nov 15:22 2014

[clug] Full Circle

I enjoyed Issue #1, which being very readable, gave me hope!



linux mailing list

Paul Rands | 11 Nov 00:43 2014

[clug] Video issues

Hi Guys, 

Yesterday I ran into some video issues in Mint 17 Mate.

If I use the standard OS bundled driver my splash screen after post is
off centre, and the login window is low res. Upon login, everything is
where it needs to be. 

If I use the nVidia driver, the splash screen
and login screens are fine, but when I finally login, my dock / taskbar
along the bottom will only appear on the screen using the analog
connection to the video card, and I cannot find where I can force it
onto the other screen, that uses the DVI connection. Also left window
will sometimes not allow icons below bottom half of screen on the DVI

Any thoughts? I am happy to continue this thread off list if
a running conversation isn't appropriate for the list. 

Thanks in

Paul Rands


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(Continue reading)

Paul Wayper | 10 Nov 23:00 2014

[clug] November CLUG Programmers' Special Interest Group meeting

	CLUG Programmers' Special Interest Group Meeting - 13th November 2014

Date:		13th November 2014 (Second Thursday of the month)

Time:		19:00 - 21:00 (or when it finishes)

Currently there are no talks scheduled. Would anyone like to volunteer?

Venue:		Room N101
		Computer Science and Information Technology Building
		North Road
		The Australian National University

		See for more directions and a map

Food/drink:	Pizza and soft drink/juice. Come hungry and bring 
		about $6 to cover the cost of your share if you want 

If you would like to give a talk at a future meeting, please email me.


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Paul Wayper | 9 Nov 23:00 2014

[clug] Anyone want to give a talk for this week's PSIG meeting?


Currently there is no talk scheduled for this week's PSIG meeting.

If you'd like to give a talk at this week's meeting, or a future meeting,
please drop me a line.


Paul Wayper

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