Help!

Hi guys I have a problem, on my laptop and I have Linux and my Arduino software is 1.6.9. So I was in the middle of finishing up this simple project for the LED bar graph and Arduino provided the instructions and the code for it (here's the link for the project: https://www.arduino.cc/en/Tutorial/BarGraph). while it was uploading an error message poped up:

/opt/arduino-1.6.9/hardware/tools/avr/bin/avrdude: error while loading shared libraries: libreadline.so.6: cannot open shared object file: No such file or directory

so can somebody please help me?

Libreadline is part of linux and should be installed on your system. Use your package manager to install or reinstall it.