diff --git a/contrib/tests/shpproj.sh b/contrib/tests/shpproj.sh
index 3cfb2d2..f6aecd9 100755
--- a/contrib/tests/shpproj.sh
+++ b/contrib/tests/shpproj.sh
@@ -1,6 +1,8 @@
-#!/bin/bash
+#!/bin/sh
 
-readonly SCRIPTDIR=$(dirname "${BASH_SOURCE[0]}")
+set -eu
+
+readonly SCRIPTDIR=$(dirname "$0")
 
 "${SHPCREATE:-$top_builddir/shpcreate}" "test" point
 
diff --git a/tests/test1.sh b/tests/test1.sh
index 787892e..c21ffbc 100755
--- a/tests/test1.sh
+++ b/tests/test1.sh
@@ -1,8 +1,8 @@
-#!/bin/bash
+#!/bin/sh
 
 set -eu
 
-readonly SCRIPTDIR=$(dirname "${BASH_SOURCE[0]}")
+readonly SCRIPTDIR=$(dirname "$0")
 readonly EXPECT="${1:-$SCRIPTDIR/expect1.out}"
 readonly EG_DATA="${2:-$SCRIPTDIR/shape_eg_data}"
 
diff --git a/tests/test2.sh b/tests/test2.sh
index 7615983..9a906f9 100755
--- a/tests/test2.sh
+++ b/tests/test2.sh
@@ -1,6 +1,6 @@
-#!/bin/bash
+#!/bin/sh
 
-readonly SCRIPTDIR=$(dirname "${BASH_SOURCE[0]}")
+readonly SCRIPTDIR=$(dirname "$0")
 readonly EXPECT="${1:-$SCRIPTDIR/expect2.out}"
 
 for i in 0 1 2 3 4 5 6 7 8 9 10 11 12 13; do
diff --git a/tests/test3.sh b/tests/test3.sh
index fa2bed0..023dcdf 100755
--- a/tests/test3.sh
+++ b/tests/test3.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 #
 #	Use example programs to create a very simple dataset that
@@ -7,7 +7,7 @@
 
 set -eu
 
-readonly SCRIPTDIR=$(dirname "${BASH_SOURCE[0]}")
+readonly SCRIPTDIR=$(dirname "$0")
 readonly EXPECT="${1:-$SCRIPTDIR/expect3.out}"
 
 {