Git: remove untracked files

Preview files that will be deleted (dry-run)
git clean -fn
Real forced cleanup
git clean -f
git help clean
Original solution is here

Debian + XFCE xscreensaver alternative screen lock

Step one
sudo apt-get purge xscreensaver xscreensaver-data
Step two
sudo apt-get install light-locker
Step three
# which light-locker-command 
Step four
Bind global hotkey (keyboard settings for XFCE case) for command /usr/bin/light-locker-command -l
Based on this solution

Debian: Decoupling VLC volume and system volume

Step 1
vim /etc/pulse/daemon.conf
Then find and change line with flat-volumes to
flat-volumes = no
After that we have to restart pulseaudio without restart
pulseaudio -k
pulseaudio -D
Source solution note is here

How to extract .tar.xz to selected folder?

It's simple
tar -xJvf archive-file.tar.xz -C ~/dest/folder/name
Also simple for regular .tar.gz files
tar -xzvf archive-file.tar.gz -C ~/dest/folder/name

How to install Plank Dock on Debian 8 - simple dock for Debian

Plank homepage is here:
0. Download & extract sources
1. Install dependencies
sudo apt-get install automake gnome-common intltool pkg-config valac libbamf3-dev libdbusmenu-gtk3-dev libgdk-pixbuf2.0-dev libgee-dev libglib2.0-dev libgtk-3-dev libwnck-3-dev libx11-dev libgee-0.8-dev
2. Compile and install
sudo make install
3. Update shared libraries
sudo ldconfig
4. Run plank, or plank preferences window
plank &
plank --preferences
Source solution is here