Fixing the reported problem is to download the Powerline project fonts and install them in the system, as the The fonts in this project provide custom symbols. Let's take the steps:

Download fonts

First, download the fonts. These can be obtained from the project link in the github or from the command:

git clone https://github.com/powerline/fonts.git

Installation

After obtaining the source package, you must run the .install file for it to install them. The ~/.fonts directory will be created, if it does not exist. This directory is used in linux for font installation.

Terminal Configuration

Change the font type used in your command terminal. In the case of using the gnome-terminal, you go to Edit > Profile Preferences and edit the font type for one of the Powerline fonts. In my case, I chose the source Meslo LG S Regular for Powerline .

Result

The result is a more elegant, more useful status bar that allows faster identification of editing modes used at the time of text editing, giving you the possibility to increase productivity.

References

link