diff --git a/scripts/hooks.sh b/scripts/hooks.sh
index 845ead9..2ed626e 100644
--- a/scripts/hooks.sh
+++ b/scripts/hooks.sh
@@ -42,10 +42,10 @@ __resh_collect() {
     #__RESH_GIT_TOPLEVEL="$(git rev-parse --show-toplevel)"
     #__RESH_GIT_TOPLEVEL_EXIT_CODE=$?
 
-    if [ -n "$ZSH_VERSION" ]; then
+    if [ -n "${ZSH_VERSION-}" ]; then
         # assume Zsh
         local __RESH_PID="$$" # current pid
-    elif [ -n "$BASH_VERSION" ]; then
+    elif [ -n "${BASH_VERSION-}" ]; then
         # assume Bash
         if [ "${BASH_VERSINFO[0]}" -ge "4" ]; then
             # $BASHPID is only available in bash4+
diff --git a/scripts/util.sh b/scripts/util.sh
index 037ff22..0694f99 100644
--- a/scripts/util.sh
+++ b/scripts/util.sh
@@ -9,7 +9,13 @@ __resh_get_pid() {
         local __RESH_PID="$$" # current pid
     elif [ -n "${BASH_VERSION-}" ]; then
         # assume Bash
-        local __RESH_PID="$BASHPID" # current pid
+        if [ "${BASH_VERSINFO[0]}" -ge "4" ]; then
+            # $BASHPID is only available in bash4+
+            # $$ is fairly similar so it should not be an issue
+            local __RESH_PID="$BASHPID" # current pid
+        else
+            local __RESH_PID="$$" # current pid
+        fi
     fi
     echo "$__RESH_PID"
 }