diff --git a/Makefile.am b/Makefile.am
index b419d0c..7fa633a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -210,7 +210,8 @@ FULL_TESTS =                                    \
   tests/50-redirect-in.sh                       \
   tests/50-redirect-append.sh                   \
   tests/50-redirect-pipe.sh                     \
-  tests/50-redirect-merge.sh                    \
+  tests/50-redirect-sed.sh                      \
+  tests/50-redirect-space.sh                    \
   tests/50-redirect-in-out.sh                   \
   tests/60-function.sh                          \
   tests/60-function-at.sh                       \
@@ -223,6 +224,7 @@ FULL_TESTS =                                    \
   tests/70-slash.sh                             \
   tests/70-slash-string.sh                      \
   tests/70-slash-string-slash.sh                \
+  tests/100-cd.sh                               \
   tests/100-cd-foo.sh                           \
   tests/100-test.sh                             \
   tests/100-test-file.sh                        \
@@ -247,10 +249,7 @@ XFAIL_TESTS =                                   \
 # that pass or fail based on environmental
 # factors.
 BROKEN_TESTS =                                  \
-  tests/10-if-redirect.sh                       \
-  tests/50-redirect-sed.sh                      \
-  tests/50-redirect-space.sh                    \
-  tests/100-cd.sh
+  tests/50-redirect-merge.sh
 
 EXTRA_DIST =                                    \
   scripts/gash.in
diff --git a/gash/environment.scm b/gash/environment.scm
index 7239def..2e31f8b 100644
--- a/gash/environment.scm
+++ b/gash/environment.scm
@@ -108,7 +108,9 @@
     (alist->hash-table
      (map (match-lambda
             ((name . value) `(,name . ,(vector value #t #f))))
-          (append `(("PWD" . ,(initial-pwd env)))
+          (append `(("PWD" . ,(initial-pwd env))
+                    ("SHELL" . ,(car (command-line)))
+                    ("SHELLOPTS" . ""))
                   env)))))
 
 (define *variables* (initial-variables))
diff --git a/tests/100-cd.sh b/tests/100-cd.sh
index 16911ea..1817731 100644
--- a/tests/100-cd.sh
+++ b/tests/100-cd.sh
@@ -1,2 +1,2 @@
-cd /bin
+cd /tmp
 pwd
diff --git a/tests/100-cd.stdout b/tests/100-cd.stdout
index 5e56e04..ceeb05b 100644
--- a/tests/100-cd.stdout
+++ b/tests/100-cd.stdout
@@ -1 +1 @@
-/bin
+/tmp
diff --git a/tests/50-redirect-in-out.sh b/tests/50-redirect-in-out.sh
index 7d81744..6aa8934 100644
--- a/tests/50-redirect-in-out.sh
+++ b/tests/50-redirect-in-out.sh
@@ -1,3 +1,3 @@
-cat < tests/data/foo > bar
-cat bar
-rm bar
+cat < tests/data/foo > /tmp/bar$$
+cat /tmp/bar$$
+rm /tmp/bar$$
diff --git a/tests/50-redirect-sed.sh b/tests/50-redirect-sed.sh
index f66236a..ee22797 100644
--- a/tests/50-redirect-sed.sh
+++ b/tests/50-redirect-sed.sh
@@ -1,5 +1,6 @@
+unset DESTDIR
 sed \
-    -e "s,^#! /bin/sh,#! /bin/gash," \
+    -e "s,^#! /bin/sh,#! /bin/GASH," \
     tests/data/diff.scm > $DESTDIR/tmp/diff.scm
 cat $DESTDIR/tmp/diff.scm
 rm $DESTDIR/tmp/diff.scm
diff --git a/tests/50-redirect-sed.stdout b/tests/50-redirect-sed.stdout
index 800bdd8..bfc05fe 100644
--- a/tests/50-redirect-sed.stdout
+++ b/tests/50-redirect-sed.stdout
@@ -1,3 +1,3 @@
-#! /bin/gash
+#! /bin/GASH
 !#
 
diff --git a/tests/50-redirect-space.sh b/tests/50-redirect-space.sh
index fe40da0..7451564 100644
--- a/tests/50-redirect-space.sh
+++ b/tests/50-redirect-space.sh
@@ -1,3 +1,3 @@
-echo foo > bar
-cat bar
-rm bar
+echo foo > /tmp/bar$$
+cat /tmp/bar$$
+rm /tmp/bar$$
diff --git a/tests/50-redirect.sh b/tests/50-redirect.sh
index da5cff4..6aaecd9 100644
--- a/tests/50-redirect.sh
+++ b/tests/50-redirect.sh
@@ -1,3 +1,3 @@
-echo foo 1>./bar
-cat bar
-rm bar
+echo foo 1>/tmp/bar$$
+cat /tmp/bar$$
+rm /tmp/bar$$
diff --git a/tests/data/diff.scm b/tests/data/diff.scm
index c7efd07..bfc05fe 100644
--- a/tests/data/diff.scm
+++ b/tests/data/diff.scm
@@ -1,3 +1,3 @@
-#! /bin/sh
+#! /bin/GASH
 !#