what software used for ocr on linux

[Hart Larry]

Well, here's what happens if I type
ocrfeeder-cli --version
/usr/lib/python2.7/dist-packages/gtk-2.0/gtk/__init__.py:57: GtkWarning: could 
not open display
   warnings.warn(str(e), _gtk.Warning)
ocrfeeder-cli 0.7.11
Back again live: Why would a commandline version have anything to do with gtk, 
or is their something I would need to configure? Thanks in advance
Hart