diff --git a/tests/mv/setup b/tests/mv/setup
index 57849e129..6da3218e1 100755
--- a/tests/mv/setup
+++ b/tests/mv/setup
@@ -8,7 +8,12 @@
 : ${MKDIR=mkdir}
 
 # Try these
-: ${CANDIDATE_TMP_DIRS="$TMPDIR /tmp /var/tmp /usr/tmp $HOME"}
+: ${CANDIDATE_TMP_DIRS=not_set
+
+# Work around a bug in the way Ultrix4.3a's /bin/sh handles multi-word
+# variables set with ${VAR="VALUE"}
+test "$CANDIDATE_TMP_DIRS" = not_set \
+  && ${CANDIDATE_TMP_DIRS="$TMPDIR /tmp /var/tmp /usr/tmp $HOME"}
 
 other_partition_tmpdir=