diff --git a/cmd/grill/flags.go b/cmd/grill/flags.go
index 34713c5..e5e8baf 100644
--- a/cmd/grill/flags.go
+++ b/cmd/grill/flags.go
@@ -31,7 +31,7 @@ var opts = struct {
 	no:          flags.Bool("no", false, "answer no to all questions (unsupported)"),
 	preserveEnv: flags.Bool("preserve-env", false, "don't reset common environment variables"),
 	keepTmpdir:  flags.Bool("keep-tmpdir", false, "keep temporary directories"),
-	shell:       flags.String("shell", "/bin/sh", "shell to use for running tests (unsupported)"),
+	shell:       flags.String("shell", "/bin/sh", "shell to use for running tests"),
 	shellOpts:   flags.String("shell-opts", "", "arguments to invoke shell with (unsupported)"),
 	xunitFile:   flags.String("xunit-file", "", "path to write xUnit XML output (unsupported)"),
 	indent:      flags.Int("indent", 2, "number of spaces to use for indentation (unsupported)"),
diff --git a/cmd/grill/main.go b/cmd/grill/main.go
index f493ac9..6c021c0 100644
--- a/cmd/grill/main.go
+++ b/cmd/grill/main.go
@@ -58,7 +58,7 @@ func Main(a []string, stdout, stderr io.Writer) int {
 		return 2
 	}
 
-	context, err := grill.DefaultTestContext("bash", stdout, stderr)
+	context, err := grill.DefaultTestContext(*opts.shell, stdout, stderr)
 	if err != nil {
 		log.Println(err)
 		return 1
@@ -89,6 +89,10 @@ func Main(a []string, stdout, stderr io.Writer) int {
 			if err := suite.WriteErr(); err != nil {
 				log.Println(err)
 			}
+		} else {
+			if err := suite.RemoveErr(); err != nil {
+				log.Println(err)
+			}
 		}
 	}
 
diff --git a/internal/grill/grill.go b/internal/grill/grill.go
index 0e2e22b..419104d 100644
--- a/internal/grill/grill.go
+++ b/internal/grill/grill.go
@@ -127,6 +127,14 @@ func (suite TestSuite) WriteErr() error {
 	return nil
 }
 
+// RemoveErr removes the matching .err file, if it exists.
+func (suite TestSuite) RemoveErr() error {
+	if err := os.Remove(suite.Name + ".err"); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
 // WriteReport writes out a report on the overall grill run.
 //
 // Setting quiet to true will hide the suite diffs
diff --git a/tests/errfile.t b/tests/errfile.t
index 085e36f..782fff9 100644
--- a/tests/errfile.t
+++ b/tests/errfile.t
@@ -1,14 +1,27 @@
 
-  $ cp $TESTDIR/errfile/*.t .
+  $ mkdir sub
+  $ echo '  $ true' > sub/pass.t
+  $ echo '  $ false' > sub/fail.t
 
-  $ grill pass.t >/dev/null 2>&1
-
-  $ grill fail.t >/dev/null 2>&1
+  $ grill -quiet sub/*.t
+  !.
+  # Ran 2 tests, 0 skipped, 1 failed.
   [1]
 
 Error files are written out only for failed suites.
 
-  $ ls
+  $ ls sub/
   fail.t
   fail.t.err
   pass.t
+
+If test starts passing, err file is removed
+
+  $ echo '  $ true' > sub/fail.t
+  $ grill -quiet sub/*.t
+  ..
+  # Ran 2 tests, 0 skipped, 0 failed.
+
+  $ ls sub/
+  fail.t
+  pass.t
diff --git a/tests/errfile/fail.t b/tests/errfile/fail.t
deleted file mode 100644
index a8963da..0000000
--- a/tests/errfile/fail.t
+++ /dev/null
@@ -1 +0,0 @@
-  $ false
diff --git a/tests/errfile/pass.t b/tests/errfile/pass.t
deleted file mode 100644
index 190b9ca..0000000
--- a/tests/errfile/pass.t
+++ /dev/null
@@ -1 +0,0 @@
-  $ true
diff --git a/tests/shell.t b/tests/shell.t
new file mode 100644
index 0000000..7486c8f
--- /dev/null
+++ b/tests/shell.t
@@ -0,0 +1,19 @@
+-shell option sets the interpreter used to run the test.
+
+  $ cat > check-sh.t <<EOF
+  >   $ echo \$0
+  >   /bin/sh (glob)
+  > EOF
+
+  $ cat > check-bash.t <<EOF
+  >   $ echo \$0
+  >   /bin/bash (glob)
+  > EOF
+
+  $ grill check-sh.t
+  .
+  # Ran 1 test, 0 skipped, 0 failed.
+
+  $ grill -shell=/bin/bash check-bash.t
+  .
+  # Ran 1 test, 0 skipped, 0 failed.