Tuesday, March 31, 2015

Remmina connection problem

After the latest update on my Ubuntu 14.04 Remmina would not connect to one of my Windows computers. I remembered having had this problem before, but was not able to remember the solution. (Even though I knew the solution was a very simple one.)

So I started googling and after a while I found the very simple solution to this problem.

After updating the computer my SSL certificate had been changed, which resulted in Remmina trying to authenticate itself with an invalid certificate/key.

When Remmina tries to connect to the Win PC it it uses the stored key in the file ~/.freerdp/known_hosts for authenticating itself to the remote computer.

Editing this file, by removing the key associated with the computer I tried to connect to, forced Remmina to ask my permission before accepting the other computer's key.

Steps to fix the problem: 

  1. Open the file: ~/.freerdp/known_hosts 
  2. Delete the key entry for the remote computer 
  3. Connect to remote computer by accepting the remote cert/key. 

Very simple to do but unfortunately just as simple to forget.

Friday, March 13, 2015

LVM Snapshot example

If your Linux is using LVM (Logical Volume Management) testing out or setting up can be much safer if you take a snapshot of your root partition. Here's a small but helpful example to help you do this quickly.

Tuesday, February 24, 2015

SUM filtered rows in LibreOffice using SUBTOTAL

In Libre Office Calc you sometimes need to filter data using the Autofilter. And of course you would like to know the sum of the values filtered. This is where you'll want to use the SUBTOTAL() function. To get the subtotal of the filtered values you'll need to tell the subtotal function which function you would like to use on the filtered rows.

Monday, January 26, 2015

LibreOffice - using INDIRECT() for cell referencing

At times I need to summarize values from another sheet in Libre Office, and get an output that will group some values together. In my example I have a small table that could contain from 10 to 1000 rows. The table I want is to be grouped by date, and I want to know how much I have spent on a specific day.

Friday, March 7, 2014

Cleaning out linux-image-x.x.xx-xx-* files

I was suddenly denied access to my in-house web-server with a message telling me the disk is full. After a quick check with df -h I could confirm the root partition used 100%.
First I started to look for "user -files" I could remove, but found out there wasn't all that many of them. Most of the usage was in the folders /lib, /usr and /var. A quick question to my friend google took me in the direction that there could be some linux-image files no longer used that were spending my disk.
Some more searching gave me the following solution to removing these unused kernel files:

Wednesday, January 29, 2014

Personal emails - Mail Merge add-on

 About a year ago I added some info about this little add-on for thunderbird calle Merge Email. I then described how-to use the address-book to make merged emails. Since I am a bit of a fan of this add-on I'll describe using it with a csv-file.