Category Archives: Ubuntu

Building RenderDoc for Android on WSL

I cloned the repository, created build directory, set environment variables and run CMake:

git clone
cd renderdoc/
mkdir build-android
cd build-android
export JAVA_HOME=~/dev/repos/graphicsprofiler/tools/buildtools/jdk
export ANDROID_SDK=~/dev/repos/graphicsprofiler/tools/buildtools/android
export ANDROID_NDK=~/dev/repos/graphicsprofiler/tools/buildtools/android/ndk-bundle/android-ndk-r20b
export PATH=$PATH:$JAVA_HOME/bin
cmake -DBUILD_ANDROID=On -DANDROID_ABI=armeabi-v7a ..

How I installed VNC on Ubuntu 22.04

I followed this guide, opened UDP port on my Windows machine:


Connecting to Ubuntu 22.04 with Remote Desktop

I simply installed:

sudo apt install ubuntu-desktop-minimal -y
sudo apt install xrdp -y
systemctl status xrdp

and was able to connect with Remote Desktop from Windows as root user:


Creating Windows Application Icon on Ubuntu 22.04

Install magick tool:

sudo apt update
sudo apt install imagemagick

Copy *.png files to a folder, for example:


and run the following command:

convert *.png winapp.ico

OpenVPN in a Docker container

Run a docker container:

export MY_IP=$(curl -s

sudo docker run -it --rm --cap-add=NET_ADMIN -p 1194:1194/udp -e HOST_ADDR=$MY_IP --name dockovpn alekslitvinenk/openvpn

Type Ctrl+P then Ctrl+Q to turn interactive mode to daemon mode.

Determined its IP address:

sudo docker ps
sudo docker inspect dockovpn | grep IPAddress

Building QT6.4 on Ubuntu 22.04

I installed required packages:

sudo apt install build-essential
sudo apt install libx11-dev
sudo apt install ninja-build
sudo apt install openssl libssl-dev
sudo apt install libmd4c-dev libmd4c-html0-dev
sudo apt install pkg-config
sudo apt install mesa-utils libglu1-mesa-dev freeglut3-dev mesa-common-dev
sudo apt install libglew-dev libglfw3-dev libglm-dev
sudo apt install libao-dev libmpg123-dev

How I fixed my contact form

When I switched to PHP 7.4 I forgot to specify sendmail_path parameter in php.ini and my contact form stopped working. Today I found sendmail_path parameter in PHP 7.0:

cd /etc/php
find . -name "php.ini"
grep sendmail ./7.0/fpm/php.ini
sendmail_path = "/usr/sbin/sendmail -t -f ***** -i"

Converting WAV files with Sox

Source file:

soxi short-borrowed-old.wav
Input File     : 'short-borrowed-old.wav' (flac)
Channels       : 2
Sample Rate    : 44100
Precision      : 16-bit
Duration       : 00:00:00.60 = 26460 samples = 45 CDDA sectors
File Size      : 54.0k
Bit Rate       : 720k
Sample Encoding: 16-bit FLAC
Comment        : 'Comment=Processed by SoX'

Switching to PHP 7.4 on Ubuntu 16.04

Some WordPress plugins stopped working with PHP 7.0 on my Ubuntu 16.04 server and I switched to PHP 7.4 with the following commands:

sudo add-apt-repository ppa:jczaplicki/xenial-php74-temp
sudo apt-get update
sudo apt-get install php7.4 php7.4-fpm php7.4-cli php7.4-mysql php7.4-dom php7.4-mbstring -y
service php7.4-fpm status
cd /etc/php/7.4/fpm/pool.d
sudo mv www.conf www.conf.dist
sudo mv ../../../7.0/fpm/pool.d/devnote.conf .
sudo service php7.0-fpm reload
sudo service php7.4-fpm reload

“Server certificate verification failed” error with command line Git client

Some guy described the same situation about 10 years ago on and there was another discussion about 7 years ago.

First I did:

GIT_CURL_VERBOSE=1 git clone
Cloning into 'examples'...
* Couldn't find host in the .netrc file; using defaults
*   Trying
* Connected to ( port 443 (#0)
* found 129 certificates in /etc/ssl/certs/ca-certificates.crt
* found 387 certificates in /etc/ssl/certs
* ALPN, offering http/1.1
* SSL connection using TLS1.2 / ECDHE_RSA_AES_256_GCM_SHA384
* server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
* stopped the pause stream!
* Closing connection 0
fatal: unable to access '': server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none