Archive for the ‘coding’ Category

Delete “imported contacts” from LinkedIn

January 8, 2018 Leave a comment

If you ever “imported contacts”, perhaps from your GMail address book, then LinkedIn will offer you those repeatedly as new connections to “invite” to your network.

If you want to stop that, go to then select all and Delete them. Note that this will not delete anyone from your LinkedIn connections, just the pointless email contacts.

If everything went well, the above URL should now display something like “You don’t have any imported contacts”. Congratulations!

Categories: coding

Enter Unicode characters in Linux

January 4, 2018 Leave a comment

To enter symbols and letters that are not on your keyboard, GTK applications on Linux offer something like Windows ALT codes, but for all Unicode characters, including the latest emojis.

Hold down CTRL-SHIFT-u and you will see an underlined u character that is waiting for input. Type the hexadecimal Unicode value and press space. is a full collection of charts that list all Unicode characters with their codes.

Here is a cheat sheet for German:

Letter Hex code
Ä c4
ä e4
Ö d6
ö f6
Ü dc
ü fc
ß df

And here some emojis from the official Unicode chart:

Emoji Hex code Name
🙃 1f643 Upside-down face
💣 1f4a3 Bomb
🤡 1f921 Clown face

enter symbols and letters that are not on your keyboard

Categories: coding

Replace TODO in index files with Capitalized folder name

September 2, 2017 Leave a comment

for file_path in $(find -type f -name $file_name); do 
  dir=$(basename $(dirname $file_path))
  sed -i -e "s/$pattern/$word/g" $file_path

Categories: bash, coding, html Tags: , ,

Recursively compare content of two directories

August 31, 2017 Leave a comment

Command line

This requires the diff and vim packages.

diff --recursive /dir/ect/ory1 /dir/ect/ory2 > 1_vs_2.diff
vimdiff 1_vs_2.diff

Potentially useful diff options:



Install Intellij CE.

Then either Run IntelliJ Diff from the command-line.

Or from within a running Intellij window:

  • Open a common parent directory as a project
  • Select the two directories to compare
  • Right-click – Compare Directories


I often see the GPL-licensed WinMerge tool recommended, But it works only on Windows, last release was 2013 and navigation into sub-directories and file diffs is a bit clunkier than in Intellij.

Work on profit-maximizing IT systems – No thanks

July 24, 2017 Leave a comment

Recently I was contacted by a well-meaning IT recruiter (name omitted for privacy reasons) and explained why I don’t work on financial trading systems anymore:

The request

Hi Oliver,

I came across your profile in my connections this morning and I was keen to reach out to you.

I can see your current experience working with Java, I am currently working on some Core Java opportunities working on the new development of a real-time trading platform.

This opportunity would allow you to work with the latest Java technologies as well as giving the opportunity to learn Scala.

Please let me know when the best date and time to get hold of you would be so we can discuss?

Kind regards,

The response

Hello XXXX,

Is it a trading platform in the financial services sector (i.e. banking)?

If so then I have to politely decline. I have worked on trading systems for a large investment bank in the past. My role was Senior Developer / Technical Lead.

But I decided that I didn’t want to spend my limited life-time helping Wall Street traders or other folks whose only business is to make more money for themselves and their (usually already wealthy) investors.

I currently work on systems that support the Canadian Search & Rescue helicopter fleet. Rescuing people’s lives or health is a cause I feel good about and that motivates me.

Please feel free to contact me again if you come across job openings that contribute to the common good.

Oliver Doepner

Categories: coding, opinion Tags: , ,

Testing HTML5 / CSS3 editor BlueGriffon

July 21, 2017 Leave a comment

I used to use the now-outdated Mozilla based editor Kompozer, which was a bug-fix fork of Nvu.

Today I realized that in the meantime (since 2015) the Nvu author Daniel Glazman has developed BlueGriffon, an Open Source next-generation Web Editor based on the current rendering engine of Firefox.

I just installed it on Windows at work and my Debian laptop at home and plan to give it a try.

If it is easy to use and generates clean standards-compliant code, I might use it for Web UI mock-ups and other prototyping. :)

Categories: apps, coding, css, firefox, gui, html Tags: ,

Trigger Camel route from command line

July 17, 2017 Leave a comment

Let’s say we have an Apache Camel route with an entry point like this:

    // other route steps 

How to trigger “direct:start” from the command line?


The JMX instrumentation agent is enabled in Camel by default.
In Camel 2.9+ no special jars are required for JMX.
For details, see the Camel JMX documentation.

  • Determine the process id of your Camel Java process.
  • Determine which user id your Camel process is running as.
  • Download or build the jmxterm tool. You need the “uber” jar.

On the same computer and as the same user, execute jmxterm like this:

java -jar jmxterm-*-uber.jar -l ${pid} -i jmxterm-script.txt

With a file jmxterm-script.txt like this:

bean org.apache.camel:context=camel-1,name="camel-1",type=context
run sendStringBody "direct:start" ""

This calls sendStringBody(..) on the ManagedCamelContext and triggers the route for you.

Categories: coding, java Tags: , ,