It seems computer security is as hot as ever topic. One of ideas that constantly float around is that systems will never be secure, that there will always be someone who is going to whistle nuclear launch codes magically with mystical juju’s called zero days. To me that sounds like…


Usually European schools offer decent education. Although it is not top of the food chain Stanford or what not American it is not bad. Like food at mensa. I mean we need to be honest, can’t be grumpy about it and ungrateful.

What in general pan European school system lacks…


Once we develop apps usually we pick a framework and set of tools. Like the one below. We have usually Lodash inside and bunch of other things.

One of things that stand out after prolonged usage is that some of these are used more than the others. Some make you…


I can’t remember how many times I searched for how to get certbot get certificate with docker and its always somewhere hard to find :-D

Here it is in more convenient place stashed so one can copy paste

docker run -it — rm — name certbot -v “/etc/letsencrypt:/etc/letsencrypt” -v “/var/lib/letsencrypt:/var/lib/letsencrypt” -p 443:443 -p 80:80 certbot/certbot certonly — standalone — preferred-challenges http -d mysite.com

This will put certificates in local drive and wont require intervention from command line.


Why I think rancher is something to roll with when doing things on on prem environments?

When one wants to juggle various services and containers one few years ago had little but few alternatives. They all looked like really good but once you actually try them on its like you…


JavaScript is today very dominant language. It is everywhere and its going bigger. One could see its popularity grow and compete and overpower more traditional languages like Java. Ecosystem grew and grew more mature.

TypeScript came as advertising to solve problem of large codebases by improving productivity in such environments…


JavaScript is progressing to be king of the hill among programming languages. Before it was frowned upon by people and underdog of programming languages it grew omnipresent and evolved to dominate.

One of the reasons I’d argue is most contributing to JavaScript becoming so popular is the ease with which…


I open twitter and there is 10x everything. To try to attach my blog on the trend I’ll write something too :-D .

Here is some words I stole from a book and paraphrased. We are all different. Some are prettier than the others, some play Starcraft better, some play…


Here is some quick and dirty video editing that one can use to for example submit app preview to app store or meet constraints on video like duration and resolution.

If we want to rescale our video we could do something like

ffmpeg -i preview.mov -vf scale=886:1920 video_640.mp4

if we want to strip sound we could

ffmpeg -i video_640.mp4 -an -vcodec copy output_file.mp4

if we want to add sound we could

ffmpeg -i output_file.mp4 -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 \\n-c:v copy -shortest output.mp4

if we want to change FPS we could do following

ffmpeg -y -i output.mp4 -c copy -f h264 output.h264

followed by

ffmpeg -y -r 30 -i output.h264 -c copy output3.mp4

now that we changed FPS video might be long

lets speed it up lets say 4 times

ffmpeg -i output3.mp4 -filter:v “setpts=0.20*PTS” output4.mp4

It takes a few google searches but here it is sublimed.


You might want to bundle certificate and private key together to be able to sign things and googling takes bit more than expected. Here is rundown at one place

Lets generate key for certificate by running following

openssl genrsa -out mysite.key 2048

Lets obtain signing request with this new key just generated

openssl req -new -sha256 -key mysite.key -out mysite.csr

Now to be able to have it in p12 format we should convert certificate we got from signing authority to PEM

openssl x509 -inform DER -in mysite.crt -out mysite.pem -outform PEM

Now to tie key and certificate together into one certificate that one can use to sign things

openssl pkcs12 -export -clcerts -inkey mysite.key -in mysite.pem -out mysite.p12 -name “My Site”

enjoy :-)

Nikola Mandic

computer user

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