diff --git a/miniupnpd/netfilter_nft/scripts/nft_delete_chain.sh b/miniupnpd/netfilter_nft/scripts/nft_delete_chain.sh
index b2e3a2b..aaf3e5d 100755
--- a/miniupnpd/netfilter_nft/scripts/nft_delete_chain.sh
+++ b/miniupnpd/netfilter_nft/scripts/nft_delete_chain.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-. $(dirname "$0")/miniupnpd_functions.sh
+. "$(dirname "$0")/miniupnpd_functions.sh"
 
 # Prerouting
 $NFT delete chain inet $NAT_TABLE $PREROUTING_CHAIN
diff --git a/miniupnpd/netfilter_nft/scripts/nft_display.sh b/miniupnpd/netfilter_nft/scripts/nft_display.sh
index b51218e..a74a8d1 100755
--- a/miniupnpd/netfilter_nft/scripts/nft_display.sh
+++ b/miniupnpd/netfilter_nft/scripts/nft_display.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-. $(dirname "$0")/miniupnpd_functions.sh
+. "$(dirname "$0")/miniupnpd_functions.sh"
 
 # Prerouting
 $NFT list chain inet $NAT_TABLE $PREROUTING_CHAIN
diff --git a/miniupnpd/netfilter_nft/scripts/nft_flush.sh b/miniupnpd/netfilter_nft/scripts/nft_flush.sh
index f2fbcff..a5d3361 100755
--- a/miniupnpd/netfilter_nft/scripts/nft_flush.sh
+++ b/miniupnpd/netfilter_nft/scripts/nft_flush.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-. $(dirname "$0")/miniupnpd_functions.sh
+. "$(dirname "$0")/miniupnpd_functions.sh"
 
 $NFT flush chain inet $TABLE $CHAIN
 $NFT flush chain inet $NAT_TABLE $PREROUTING_CHAIN
diff --git a/miniupnpd/netfilter_nft/scripts/nft_init.sh b/miniupnpd/netfilter_nft/scripts/nft_init.sh
index 839fbe9..4899e7f 100755
--- a/miniupnpd/netfilter_nft/scripts/nft_init.sh
+++ b/miniupnpd/netfilter_nft/scripts/nft_init.sh
@@ -5,7 +5,7 @@
 # 'add' doesn't raise an error if the object already exists. 'create' does.
 #
 
-. $(dirname "$0")/miniupnpd_functions.sh
+. "$(dirname "$0")/miniupnpd_functions.sh"
 
 $NFT --check list table inet $TABLE > /dev/null 2>&1
 if [ $? -eq "0" ]
diff --git a/miniupnpd/netfilter_nft/scripts/nft_removeall.sh b/miniupnpd/netfilter_nft/scripts/nft_removeall.sh
index 8a6beff..61e88d0 100755
--- a/miniupnpd/netfilter_nft/scripts/nft_removeall.sh
+++ b/miniupnpd/netfilter_nft/scripts/nft_removeall.sh
@@ -5,7 +5,7 @@
 # Do not disturb other existing structures in nftables, e.g. those created by firewalld
 #
 
-. $(dirname "$0")/miniupnpd_functions.sh
+. "$(dirname "$0")/miniupnpd_functions.sh"
 
 $NFT --check list table inet $TABLE > /dev/null 2>&1
 if [ $? -eq "0" ]