diff --git a/Containers/mastercontainer/start.sh b/Containers/mastercontainer/start.sh
index c36331fe..6ded5bfd 100755
--- a/Containers/mastercontainer/start.sh
+++ b/Containers/mastercontainer/start.sh
@@ -40,9 +40,10 @@ if ! docker info &>/dev/null; then
     exit 1
 fi
 API_VERSION_FILE="$(find ./ -name DockerActionManager.php | head -1)"
-API_VERSION="$(grep -oP 'const API_VERSION.*\;' "$API_VERSION_FILE" | grep -oP [0-9]+.[0-9]+ | head -1)"
+API_VERSION="$(grep -oP 'const API_VERSION.*\;' "$API_VERSION_FILE" | grep -oP '[0-9]+.[0-9]+' | head -1)"
+# shellcheck disable=SC2001
 API_VERSION_NUMB="$(echo "$API_VERSION" | sed 's/\.//')"
-LOCAL_API_VERSION_NUMB="$(docker version | grep -i "api version" | grep -oP [0-9]+.[0-9]+ | head -1 | sed 's/\.//')"
+LOCAL_API_VERSION_NUMB="$(docker version | grep -i "api version" | grep -oP '[0-9]+.[0-9]+' | head -1 | sed 's/\.//')"
 if [ -n "$LOCAL_API_VERSION_NUMB" ] && [ -n "$API_VERSION_NUMB" ]; then
     if ! [ "$LOCAL_API_VERSION_NUMB" -ge "$API_VERSION_NUMB" ]; then
         echo "Docker v$API_VERSION is not supported by your docker engine. Cannot proceed."
@@ -71,12 +72,12 @@ chown root:root -R /mnt/docker-aio-config/certs/
 GENERATED_CERTS="/mnt/docker-aio-config/certs"
 TMP_CERTS="/etc/apache2/certs"
 mkdir -p "$GENERATED_CERTS"
-cd "$GENERATED_CERTS"
+cd "$GENERATED_CERTS" || exit 1
 if ! [ -f ./ssl.crt ] && ! [ -f ./ssl.key ]; then
     openssl req -new -newkey rsa:4096 -days 3650 -nodes -x509 -subj "/C=DE/ST=BE/L=Local/O=Dev/CN=nextcloud.local" -keyout ./ssl.key -out ./ssl.crt
 fi
 if [ -f ./ssl.crt ] && [ -f ./ssl.key ]; then
-    cd "$TMP_CERTS"
+    cd "$TMP_CERTS" || exit 1
     rm ./ssl.crt
     rm ./ssl.key
     cp "$GENERATED_CERTS/ssl.crt" ./
diff --git a/Containers/nextcloud/entrypoint.sh b/Containers/nextcloud/entrypoint.sh
index 6d5d34d5..2e830078 100644
--- a/Containers/nextcloud/entrypoint.sh
+++ b/Containers/nextcloud/entrypoint.sh
@@ -50,7 +50,8 @@ if ! [ -f "/mnt/ncdata/skip.update" ]; then
             NEXT_MAJOR="$((INSTALLED_MAJOR + 1))"
             curl -fsSL -o nextcloud.tar.bz2 "https://download.nextcloud.com/server/releases/latest-${NEXT_MAJOR}.tar.bz2"
             curl -fsSL -o nextcloud.tar.bz2.asc "https://download.nextcloud.com/server/releases/latest-${NEXT_MAJOR}.tar.bz2.asc"
-            export GNUPGHOME="$(mktemp -d)"
+            GNUPGHOME="$(mktemp -d)"
+            export GNUPGHOME
             # gpg key from https://nextcloud.com/nextcloud.asc
             gpg --batch --keyserver keyserver.ubuntu.com --recv-keys 28806A878AE423A28372792ED75899B9A724937A
             gpg --batch --verify nextcloud.tar.bz2.asc nextcloud.tar.bz2
diff --git a/Containers/nextcloud/start.sh b/Containers/nextcloud/start.sh
index 33171688..10ac59c4 100644
--- a/Containers/nextcloud/start.sh
+++ b/Containers/nextcloud/start.sh
@@ -12,7 +12,8 @@ if ! bash /entrypoint.sh; then
 fi
 
 # Correctly set CPU_ARCH for notify_push
-export CPU_ARCH="$(uname -m)"
+CPU_ARCH="$(uname -m)"
+export CPU_ARCH
 if [ -z "$CPU_ARCH" ]; then
     echo "Could not get processor architecture. Exiting."
     exit 1
diff --git a/Containers/postgresql/start.sh b/Containers/postgresql/start.sh
index 20db843b..1044e294 100644
--- a/Containers/postgresql/start.sh
+++ b/Containers/postgresql/start.sh
@@ -19,6 +19,7 @@ if ! [ -w "$DUMP_DIR" ]; then
 fi
 
 # Test if some things match
+# shellcheck disable=SC2235
 if ( [ -f "$DATADIR/PG_VERSION" ] && [ "$PG_MAJOR" != "$(cat "$DATADIR/PG_VERSION")" ] ) \
 || ( ! [ -f "$DATADIR/PG_VERSION" ] && [ -f "$DUMP_FILE" ] ); then
     # The DUMP_file must be provided
@@ -41,7 +42,7 @@ if ( [ -f "$DATADIR/PG_VERSION" ] && [ "$PG_MAJOR" != "$(cat "$DATADIR/PG_VERSIO
     set -e
 
     # Remove old database files
-    rm -rf "$DATADIR/"*
+    rm -rf "${DATADIR:?}/"*
 
     # Change database port to a random port temporarily
     export PGPORT=11000
@@ -69,7 +70,7 @@ fi
 # Cover the last case
 if ! [ -f "$DATADIR/PG_VERSION" ] && ! [ -f "$DUMP_FILE" ]; then
     # Remove old database files if somehow there should be some
-    rm -rf "$DATADIR/"*
+    rm -rf "${DATADIR:?}/"*
 fi
 
 # Catch docker stop attempts