MatterMost native chat client (like slack/IRC) on Linux


So today I bumped into 

This is like slack (sort of modern IRC) but open source.

I also found that is has a Linux Native client:

To get it to work, I just downloaded it, extracted it and ran the included “Mattermost” binary.

Connecting it to Eclipse was mildly counter intuitive.

When faced witht he ‘Teams’ dialogue, I thought I had to  type in Name OR URL, but it turns out you type in both. The name is just an alias ex “Eclipse”, and for URL you put in:


After you joined, you can find some channels to join. In my case:

Platform: SWT

Now when someone wants to chat with you, you can give them the URL:

Happy MatterMost-ing

Ramdisk for the impatient.

I have a pci-e based storage working at close to 1000mb/s (Mac Pro). I do lots of GCC/make compilations. What if you want things even faster than with a pcie? Then ramdisk is your friend.

My results:

  • With Regular SSD:  2 minutes and 37 seconds   (on my co-worker’s machine w/Fedora)
  • With my pci-e disk: 2 minutes and 35 seconds (my Mac w/Fedora)
  • With Ramdisk:           1 minute and 15 seconds (my Mac w/Fedora)

So we have ~50% improvement in compilation time. For me, it’s worth the effort.

To set one up: Follow this guide


[code language='bash']
sudo mkdir /mnt/ramdisk
sudo mount -t tmpfs -o size=2G tmpfs /mnt/ramdisk

To see how much of it is still available:

df -h

You might want to write an rsync script to copy folders onto the ramdisk that you want fast-access to. Ex a git repo that you compile frequently, some application binaries that you run. But obviously avoid putting data onto the disk.




How to create cross-platform SWT applications packaged in a single jar in Eclipse

The deal with SWT is that you geneally create a jar that runs nativley on a single platform.

This means that if you want to create an application that works on windows/mac/linux in both 32/64 bit, then you need to compile/package jar 6 files and distribute one file per platform.

This is very cumbersome for small projects where you want a single file that runs on every platform.

The solution is to bundle the jars and load them dynamically with Mchr3k’s SWT Jar loader.

The next challenge is how to get this business working in Eclipse. Well, there is a guide for this.

Basically, you create a project with the name “HelloWorld”, you have to
download the swt jar’s and rename them to match os/version and then you
have to add a build.xml file. This takes about 30 minutes.

I followed the guide and actually got it to work.

To make life easier, I created a git-repo with a template project.  You can clone it and start a SWT project with that.

I used swt 4.4 in the project. In the future you might want to update it. To do so:

  • Download the latest jar files from Eclipse’s download site .
    • click on the most recent version, e.g ‘4’4,
    • then search for “SWT Binary and Source”
    • download the Windows 32/64 Versions,   linux x86/x86_64/GTK+ versions, Mac OS X versions
    • open the archives and extract the ‘swt.jar’ files
    • match the jar files to the jar files in the project ./gui folder. But append new version. (4.4 -> 4.x)
  • Edit the build.xml file,
    • change the “swtversion=”4.4″” to the newer version.
    • Also update <fileset dir=”./gui” includes=”swt-*-4.4.jar” />

Screen shots:



You can run the generated jar file with ‘java -jar crossSWT.jar”:

crossSWT jar


Here I had to launch the jar with a special paramater:
java -jar -XstartOnFirstThread crossSWT.jar
os x


I don’t use windows :-), but rumors has it works on windows also.

How to compile various gtk3 versions and run eclipse Apps with those (for SWT Widget testing)


When developing SWT widgets, we need to test them on various GTK versions to ensure backwards compatibility.

There are some tricks and perks involved.

Get Gtk sources

  • Go to the gtk git repo and pull the code:
    (I recommend the https version:
    (if you don’t know how to use eclipse’s EGit, read this)
  • Check out the versions that you’re interested in (e.g 2.24, 3.10, 3.4, 3.8)
    These are found in major Linux distributions (e.g ubuntu 12..).
  • For the time being, check out the newest gtk version (e.g 3.10 at the time of writing).
    (It’s easier to build a newer version than an older one)
  • Open Terminal, go to your checked out gtk branch.
    Run the following commands:

    ./configure --enable-x11-backend --enable-wayland-backend
  • The first time you run the commands, you might run into errors telling you you’re missing something on your system. Inspect to see what it runs and then install the utilities with yum.
  • Now copy gtk to another place on your system. E.g ~/src/gtk2_24 This way you don’t have to recompile this business every time.
  • Now you can build the other versions and similarly copy them to ~/src/gtk*_*
  • NOTE ON gtk3.4 (and maybe older) The Wayland configuration makes certain things look more correct. But sometimes it makes building older versions (like gtk3.4) near impossible due to missing dependencies. In this case, run the configure without these:
     ./ ./configure make 

Configure Eclipse to use the gtk you compiled

  • Edit your run-configuration of the code snippet that you want to run.
  • Navigate to “Environmental Variables”
  • Click on “Add”, type in:
    path: #your_compiled_gtk      //e.g /home/lufimtse/src/gtk3_10/gtk/.libs
  • Name your configuration (I reccomend appending gtk version, e.g “ControlExample (g3-10)”)
  • It should look something like this:
    Eclipse env var
  • Now run the configuration and you should see your application rendered in gtk*.*.
    You may note that it won’t have any styling:
    java app in compiled gtk
  • The lack of styling is due to the fact that there is no theaming.
    Now sometimes you might want the compiled gtk to use your system theame to see impact of themes on looks.
    To do so, do as above except run the configuration as following:

    ./configure --prefix=/usr --sysconfdir=/etc --enable-broadway-backend --enable-x11-backend --disable-wayland-backend

    In the interest of comparison: (left native look, right bare look)
    native vs bare

  • Lastly, in your source code, you might want to verify that you’re running the compiled gtk and not your own. Use this line of code:
    System.out.println("GTK Version: " + OS.gtk_major_version() + "." + OS.gtk_minor_version() + "." + OS.gtk_micro_version());


pipe commands into clipboard

I often need to pipe commands into the clipboard. E.g when I type “pwd” to get the present working directory, I would normally select the line and then copy it into my clipboard.

After a while this became tedious so I wrote a script to make life easier. I created a bash script called “toclip”…

Continue reading