enable duplex printing

Our Student Users don’t have admin rights. So it was necessary to adapt the [UsedPrinterName].ppd file. And set the Value from  DefaultAPOptionalDuplexer: False to True.


sed -i '' 's/*search_string/*replace_string/g' /path/to/file.extension

-i ”” edit the changes into the same file (there is a blank between -i  and the double empty quote!

############ change duplex 
Printer_X=$(less /private/etc/cups/ppd/Printer_X.ppd | grep "*DefaultAPOptionalDuplexer: False")

    if [ "$Printer_X" == "*DefaultAPOptionalDuplexer: False" ] 
        echo "change Printer_X to duplex"
       	sed -i '' 's/*DefaultAPOptionalDuplexer: False/*DefaultAPOptionalDuplexer: True/g' /private/etc/cups/ppd/Printer_X.ppd
    	echo "not needed"


I use this within a login script triggered with Jamf (Loginhook). This was the only working solution I have found to enable in school lab environment.

CURRENTUSER=$(/usr/bin/python -c 'from SystemConfiguration import SCDynamicStoreCopyConsoleUser; import sys; username = (SCDynamicStoreCopyConsoleUser(None, None, None) or [None])[0]; username = [username,""][username in [u"loginwindow", None, u""]]; sys.stdout.write(username + "\n");')
su "$CURRENTUSER" -c "defaults write /Users/ws/Library/Preferences/.GlobalPreferences AppleShowAllExtensions -bool true" 
su "$CURRENTUSER" -c "killall Finder"

Tested on MacOS 10.14.5 / 10.14.6

some 3d printed parts

One of the first 3d printed things was a subdivision for a desk organizer

Desk organiser RISSLA from Ikea with 3d printed dividers…

The kinship has received a small Christmas gift
Printed coasters with Merry Christmas 2016 on it

Some random Parts


new “toy” has arrived

to be spoilt for choice

After some weeks of information gathering, switching in mind from Dremel Idea Builder 3D20 to a cheaper DIY 3D Printer and back.

Weighing of functions:
Do I really need PLA and ABS…
Dual extruder yes or no?
Open or closed systems
I don’t like to be dependent on one manufacturer. Filament in cartridges, cartridges with chips,…
The costs rise immediately if one or two “options” are active.

3D Printer – FLASHFORGE Finder

Finally, I dared the step. No high end, no DIY device. The first attempts were already very promising.

Attached some photos of the unboxing

img_2009 img_2011 img_2012
img_2013 img_2014 img_2015

Little Engineer – first use

Little obstacles with fun”

My six-year-old son, was the first tester.  He did quite well. And played in the first attempt at level 20.


We had difficulties with the engineer blocks. Since we did not know when these were detected. But after an acclimatization phase everything went quite well.


Drag and drop program elements like turn left, right, go, … is not easy at times. But my son has not stopped playing the game.


He had the greatest fun as the alien has eaten the others.

The difficulty increases with time. As more and more features are unlocked.

Little Engineer – Unboxing

The surprise package has arrived!

(I received no email notification)


Putao Technology Inc.

little engineer
surprise surprise a little engineer kit is in the box 😉

´first look
first look

storage boxes (one for the blocks and the other for the iPad holder and the camera mirror)

iPad holder

engineer blocks
engineer blocks

fully built and ready to the use

ready to use

At the first look, everything fits together perfectly. I use an old iPad2. Little Engineer is compatible with iPad 2, iPad 3, iPad 4m iPad Pro, iPad Air 1/2, iPad Mini 1/2/3/4.

All parts are made from high-quality materials, the kit has no plastic parts which break off, or has sharp edges.

the first impression is very positive

I‘m very excited when the kids will play the first time with the little engineer game.