diff --git a/hacking/env-setup b/hacking/env-setup
index 16baa9b1b7..f52c91a8b9 100644
--- a/hacking/env-setup
+++ b/hacking/env-setup
@@ -16,6 +16,7 @@ if [ -n "$BASH_SOURCE" ] ; then
     HACKING_DIR=$(dirname "$BASH_SOURCE")
 elif [ $(basename -- "$0") = "env-setup" ]; then
     HACKING_DIR=$(dirname "$0")
+# Works with ksh93 but not pdksh
 elif [ -n "$KSH_VERSION" ] && echo $KSH_VERSION | grep -qv '^@(#)PD KSH'; then
     HACKING_DIR=$(dirname "${.sh.file}")
 else
diff --git a/v2/hacking/env-setup b/v2/hacking/env-setup
index fed8e892fd..c03fa0874e 100644
--- a/v2/hacking/env-setup
+++ b/v2/hacking/env-setup
@@ -16,7 +16,8 @@ if [ -n "$BASH_SOURCE" ] ; then
     HACKING_DIR=$(dirname "$BASH_SOURCE")
 elif [ $(basename -- "$0") = "env-setup" ]; then
     HACKING_DIR=$(dirname "$0")
-elif [ -n "$KSH_VERSION" ]; then
+# Works with ksh93 but not pdksh
+elif [ -n "$KSH_VERSION" ] && echo $KSH_VERSION | grep -qv '^@(#)PD KSH'; then
     HACKING_DIR=$(dirname "${.sh.file}")
 else
     HACKING_DIR="$PWD/hacking"