How to hide the side bar in okular?

March 16, 2019 Leave a comment

When you open a PDF in okular, you have a huge side bar on the left. How to hide it? Under View there is nothing about it :(

It’s under Settings. There, untick Show Navigation Panel. There is a shortcut for toggling the side bar: F7.

Categories: linux Tags: , ,

How to append images vertically?

February 26, 2019 Leave a comment

With youtube-dl I downloaded all the videos of a YouTube playlist. I also wanted to have a screenshot with all the videos of the playlist that contains the thumbnails, the titles, etc. As the playlist contained many videos and thus they didn’t fit on one page, I took several screenshots. For example, 01.png contained videos from 1 to 9, 02.png contained videos from 10 to 18, etc.
However, instead of several screenshots, I wanted just one long screenshot with everything. How to concatenate images vertically?

Using convert from ImageMagick:

convert -append 1.png 2.png full.png

This tip is from here.

Categories: bash Tags: , ,

[latex] using accents

February 22, 2019 Leave a comment

I wanted to write a LaTeX document in Hungarian using those funny accents (áéíóöőüű), but they didn’t appear in the PDF output.



The tip is from here.

Categories: latex Tags: , ,

[manjaro] goodbye yaourt, hello yay

February 22, 2019 Leave a comment

Under Manjaro I’ve used yaourt so far to install AUR and even other packages. I’ve read there are problems with yaourt but it worked so well. However, I just heard that yaourt is not maintained any longer. So what to use instead of yaourt?

yay is very similar to yaourt in its functionalities and usage, thus it seems to be a good replacement.

I only had one issue, the output was not colored, but it was easy to fix. From the FAQ: “make sure you have the Color option in your /etc/pacman.conf“.

I even removed yaourt to force myself to use yay: “yay -R yaourt“.

yaourt was great and I’m thankful for its developers.


Categories: linux Tags: , , , , ,

finding a neovim problem

February 5, 2019 Leave a comment

Neovim has a built-in command :checkhealth that will run a detailed self-diagnosis.

I had the problem that when I started neovim, I got some Python-related error concerning the package neovim (the reddit discussion is here). With :checkhealth I could find the source of the problem easily.

Categories: vim Tags: , ,

[manjaro] convert refuses to produce PDFs

January 10, 2019 Leave a comment

Under Manjaro, I wanted to create a PDF from some JPG files. However, convert dropped an error:

$ convert *.jpg out.pdf
convert: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/408.

Edit the file /etc/ImageMagick-7/policy.xml and find the following line:

<policy domain="coder" rights="none" pattern="{PS,PS2,PS3,EPS,PDF,XPS}" />

Put it between comments (<!-- and -->) and everything is good again.

I found this solution here.

Categories: bash, linux Tags: , , ,

Advent of Code 2018 is over

December 25, 2018 Leave a comment

Similarly to last year, I participated in Advent of Code again. Last year I could finish it in time, but this year I missed some days. As today was the last day of the challenge, here is my result:


This year the exercises were harder than last year. My solutions are on GitHub: . This year I used the Nim programming language.

Categories: programming Tags: , , ,