Is there a way to check which font your shell/terminal emulator is using from the commandline?

Solution 1:

The option Use the system fixed width font is usually equal and set by org.gnome.desktop.interface.

• To get current font setting run following command:

  gsettings get org.gnome.desktop.interface monospace-font-name
  

• To set/change setting run following command (here example of increase size) :

  gsettings set org.gnome.desktop.interface monospace-font-name 'Ubuntu Mono 14'
  

As I run above command, I found font of your terminal changed (increased size)! So, gnome-terminal using that font setting.

Solution 2:

DE-independent way of getting system's preferred monospace font:

$ fc-match Monospace
DejaVuSansMono.ttf: "DejaVu Sans Mono" "Book"

Ref: ArchWiki Font configuration