Index: xdiskusage.C
--- xdiskusage.C.orig
+++ xdiskusage.C
@@ -32,7 +32,7 @@ const char* copyright = 
 #elif defined(__bsdi__)
 # define DF_COMMAND "df"
 # define DU_COMMAND "du -x"
-#elif defined(__FreeBSD__) || defined(__APPLE__)
+#elif defined(__FreeBSD__) || defined(__APPLE__) || defined(__OpenBSD__)
 # define DF_COMMAND "df -P -k -t noprocfs,devfs,fdescfs"
 # define DU_COMMAND "du -kx"
 #elif defined(SVR4) || defined(__sun)
