lilypond-usage: Using Xpdf for point and click

 
 Using Xpdf
 ..........
 
 For Xpdf on UNIX, the following should be present in ‘xpdfrc’.  On UNIX,
 this file is found either in ‘/etc/xpdfrc’ or as ‘$HOME/.xpdfrc’.
 
      urlCommand     "lilypond-invoke-editor %s"
 
    If you are using Ubuntu, it is likely that the version of Xpdf
 installed with your system crashes on every PDF file: this state has
 been persisting for several years and is due to library mismatches.
 Your best bet is to install a current ‘xpdf’ package and the
 corresponding ‘libpoppler’ package from Debian instead.  Once you have
 tested that this works, you might want to use
      sudo apt-mark hold xpdf
 in order to keep Ubuntu from overwriting it with the next ‘update’ of
 its crashing package.