diff --git a/21/apache/entrypoint.sh b/21/apache/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/21/apache/entrypoint.sh
+++ b/21/apache/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/21/fpm-alpine/entrypoint.sh b/21/fpm-alpine/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/21/fpm-alpine/entrypoint.sh
+++ b/21/fpm-alpine/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/21/fpm/entrypoint.sh b/21/fpm/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/21/fpm/entrypoint.sh
+++ b/21/fpm/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/22/apache/entrypoint.sh b/22/apache/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/22/apache/entrypoint.sh
+++ b/22/apache/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/22/fpm-alpine/entrypoint.sh b/22/fpm-alpine/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/22/fpm-alpine/entrypoint.sh
+++ b/22/fpm-alpine/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/22/fpm/entrypoint.sh b/22/fpm/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/22/fpm/entrypoint.sh
+++ b/22/fpm/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/23/apache/entrypoint.sh b/23/apache/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/23/apache/entrypoint.sh
+++ b/23/apache/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/23/fpm-alpine/entrypoint.sh b/23/fpm-alpine/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/23/fpm-alpine/entrypoint.sh
+++ b/23/fpm-alpine/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/23/fpm/entrypoint.sh b/23/fpm/entrypoint.sh
index 206e2878..b6da893b 100755
--- a/23/fpm/entrypoint.sh
+++ b/23/fpm/entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 206e2878..b6da893b 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -57,7 +57,7 @@ if expr "$1" : "apache" 1>/dev/null || [ "$1" = "php-fpm" ] || [ "${NEXTCLOUD_UP
             file_env REDIS_HOST_PASSWORD
             echo 'session.save_handler = redis'
             # check if redis host is an unix socket path
-            if [ "${REDIS_HOST:0:1}" = "/" ]; then
+            if [ "$(echo "$REDIS_HOST" | cut -c1-1)" = "/" ]; then
               if [ -n "${REDIS_HOST_PASSWORD+x}" ]; then
                 echo "session.save_path = \"unix://${REDIS_HOST}?auth=${REDIS_HOST_PASSWORD}\""
               else