diff -up asymptote-2.52/settings.cc.settings asymptote-2.52/settings.cc
--- asymptote-2.52/settings.cc.settings	2019-08-10 03:31:17.532141530 -0400
+++ asymptote-2.52/settings.cc	2019-08-10 03:31:41.767598912 -0400
@@ -95,8 +95,8 @@ const char pathSeparator=':';
 string defaultPSViewer="open";
 string defaultPDFViewer="open";
 #else  
-string defaultPSViewer="gv";
-string defaultPDFViewer="acroread";
+string defaultPSViewer="evince";
+string defaultPDFViewer="evince";
 #endif  
 string defaultGhostscript="gs";
 string defaultGhostscriptLibrary="";