diff --git a/extras/add_vpn_user.sh b/extras/add_vpn_user.sh
index ca40a5d..12a1f09 100644
--- a/extras/add_vpn_user.sh
+++ b/extras/add_vpn_user.sh
@@ -11,7 +11,7 @@
 # know how you have improved it!
 
 export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-SYS_DT="$(date +%F-%T)"
+SYS_DT=$(date +%F-%T)
 
 exiterr()  { echo "Error: $1" >&2; exit 1; }
 conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; }
diff --git a/extras/del_vpn_user.sh b/extras/del_vpn_user.sh
index 02e20cf..e176dd5 100644
--- a/extras/del_vpn_user.sh
+++ b/extras/del_vpn_user.sh
@@ -11,7 +11,7 @@
 # know how you have improved it!
 
 export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-SYS_DT="$(date +%F-%T)"
+SYS_DT=$(date +%F-%T)
 
 exiterr()  { echo "Error: $1" >&2; exit 1; }
 conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; }
diff --git a/extras/update_vpn_users.sh b/extras/update_vpn_users.sh
index fd1774d..4db4223 100644
--- a/extras/update_vpn_users.sh
+++ b/extras/update_vpn_users.sh
@@ -27,7 +27,7 @@ YOUR_PASSWORDS=''
 # =====================================================
 
 export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-SYS_DT="$(date +%F-%T)"
+SYS_DT=$(date +%F-%T)
 
 exiterr()  { echo "Error: $1" >&2; exit 1; }
 conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; }
@@ -65,12 +65,12 @@ if [ -z "$VPN_USERS" ] || [ -z "$VPN_PASSWORDS" ]; then
   exiterr "All VPN credentials must be specified. Edit the script and re-enter them."
 fi
 
-VPN_USERS="$(noquotes "$VPN_USERS")"
-VPN_USERS="$(onespace "$VPN_USERS")"
-VPN_USERS="$(noquotes2 "$VPN_USERS")"
-VPN_PASSWORDS="$(noquotes "$VPN_PASSWORDS")"
-VPN_PASSWORDS="$(onespace "$VPN_PASSWORDS")"
-VPN_PASSWORDS="$(noquotes2 "$VPN_PASSWORDS")"
+VPN_USERS=$(noquotes "$VPN_USERS")
+VPN_USERS=$(onespace "$VPN_USERS")
+VPN_USERS=$(noquotes2 "$VPN_USERS")
+VPN_PASSWORDS=$(noquotes "$VPN_PASSWORDS")
+VPN_PASSWORDS=$(onespace "$VPN_PASSWORDS")
+VPN_PASSWORDS=$(noquotes2 "$VPN_PASSWORDS")
 
 if printf '%s' "$VPN_USERS $VPN_PASSWORDS" | LC_ALL=C grep -q '[^ -~]\+'; then
   exiterr "VPN credentials must not contain non-ASCII characters."
diff --git a/extras/vpnupgrade.sh b/extras/vpnupgrade.sh
index 45b9504..a91fab2 100644
--- a/extras/vpnupgrade.sh
+++ b/extras/vpnupgrade.sh
@@ -22,10 +22,10 @@ exiterr2() { exiterr "'apt-get install' failed."; }
 
 vpnupgrade() {
 
-os_type="$(lsb_release -si 2>/dev/null)"
+os_type=$(lsb_release -si 2>/dev/null)
 if [ -z "$os_type" ]; then
-  [ -f /etc/os-release  ] && os_type="$(. /etc/os-release  && printf '%s' "$ID")"
-  [ -f /etc/lsb-release ] && os_type="$(. /etc/lsb-release && printf '%s' "$DISTRIB_ID")"
+  [ -f /etc/os-release  ] && os_type=$(. /etc/os-release  && printf '%s' "$ID")
+  [ -f /etc/lsb-release ] && os_type=$(. /etc/lsb-release && printf '%s' "$DISTRIB_ID")
 fi
 if ! printf '%s' "$os_type" | head -n 1 | grep -qiF -e ubuntu -e debian -e raspbian; then
   exiterr "This script only supports Ubuntu and Debian."
@@ -77,8 +77,8 @@ case "$SWAN_VER" in
     ;;
 esac
 
-ipsec_ver="$(/usr/local/sbin/ipsec --version 2>/dev/null)"
-ipsec_ver_short="$(printf '%s' "$ipsec_ver" | sed -e 's/Linux Libreswan/Libreswan/' -e 's/ (netkey) on .*//')"
+ipsec_ver=$(/usr/local/sbin/ipsec --version 2>/dev/null)
+ipsec_ver_short=$(printf '%s' "$ipsec_ver" | sed -e 's/Linux Libreswan/Libreswan/' -e 's/ (netkey) on .*//')
 if ! printf '%s' "$ipsec_ver" | grep -q "Libreswan"; then
   exiterr "This script requires Libreswan already installed."
 fi
@@ -202,7 +202,7 @@ EOF
 if [ "$(packaging/utils/lswan_detect.sh init)" = "systemd" ]; then
   apt-get -yq install libsystemd-dev || exiterr2
 fi
-NPROCS="$(grep -c ^processor /proc/cpuinfo)"
+NPROCS=$(grep -c ^processor /proc/cpuinfo)
 [ -z "$NPROCS" ] && NPROCS=1
 make "-j$((NPROCS+1))" -s base && make -s install-base
 
diff --git a/extras/vpnupgrade_centos.sh b/extras/vpnupgrade_centos.sh
index a3eb542..fb33eb9 100644
--- a/extras/vpnupgrade_centos.sh
+++ b/extras/vpnupgrade_centos.sh
@@ -68,8 +68,8 @@ case "$SWAN_VER" in
     ;;
 esac
 
-ipsec_ver="$(/usr/local/sbin/ipsec --version 2>/dev/null)"
-ipsec_ver_short="$(printf '%s' "$ipsec_ver" | sed -e 's/Linux Libreswan/Libreswan/' -e 's/ (netkey) on .*//')"
+ipsec_ver=$(/usr/local/sbin/ipsec --version 2>/dev/null)
+ipsec_ver_short=$(printf '%s' "$ipsec_ver" | sed -e 's/Linux Libreswan/Libreswan/' -e 's/ (netkey) on .*//')
 if ! printf '%s' "$ipsec_ver" | grep -q "Libreswan"; then
   exiterr "This script requires Libreswan already installed."
 fi
@@ -199,7 +199,7 @@ USE_DNSSEC = false
 USE_DH31 = false
 USE_GLIBC_KERN_FLIP_HEADERS = true
 EOF
-NPROCS="$(grep -c ^processor /proc/cpuinfo)"
+NPROCS=$(grep -c ^processor /proc/cpuinfo)
 [ -z "$NPROCS" ] && NPROCS=1
 make "-j$((NPROCS+1))" -s base && make -s install-base
 
diff --git a/vpnsetup.sh b/vpnsetup.sh
index 3d3db0e..8bb8bca 100755
--- a/vpnsetup.sh
+++ b/vpnsetup.sh
@@ -34,7 +34,7 @@ YOUR_PASSWORD=''
 # =====================================================
 
 export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-SYS_DT="$(date +%F-%T)"
+SYS_DT=$(date +%F-%T)
 
 exiterr()  { echo "Error: $1" >&2; exit 1; }
 exiterr2() { exiterr "'apt-get install' failed."; }
@@ -48,10 +48,10 @@ check_ip() {
 
 vpnsetup() {
 
-os_type="$(lsb_release -si 2>/dev/null)"
+os_type=$(lsb_release -si 2>/dev/null)
 if [ -z "$os_type" ]; then
-  [ -f /etc/os-release  ] && os_type="$(. /etc/os-release  && printf '%s' "$ID")"
-  [ -f /etc/lsb-release ] && os_type="$(. /etc/lsb-release && printf '%s' "$DISTRIB_ID")"
+  [ -f /etc/os-release  ] && os_type=$(. /etc/os-release  && printf '%s' "$ID")
+  [ -f /etc/lsb-release ] && os_type=$(. /etc/lsb-release && printf '%s' "$DISTRIB_ID")
 fi
 if ! printf '%s' "$os_type" | head -n 1 | grep -qiF -e ubuntu -e debian -e raspbian; then
   exiterr "This script only supports Ubuntu and Debian."
@@ -95,9 +95,9 @@ fi
 
 if [ -z "$VPN_IPSEC_PSK" ] && [ -z "$VPN_USER" ] && [ -z "$VPN_PASSWORD" ]; then
   bigecho "VPN credentials not set by user. Generating random PSK and password..."
-  VPN_IPSEC_PSK="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 20)"
+  VPN_IPSEC_PSK=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 20)
   VPN_USER=vpnuser
-  VPN_PASSWORD="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)"
+  VPN_PASSWORD=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)
 fi
 
 if [ -z "$VPN_IPSEC_PSK" ] || [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then
@@ -207,7 +207,7 @@ EOF
 if [ "$(packaging/utils/lswan_detect.sh init)" = "systemd" ]; then
   apt-get -yq install libsystemd-dev || exiterr2
 fi
-NPROCS="$(grep -c ^processor /proc/cpuinfo)"
+NPROCS=$(grep -c ^processor /proc/cpuinfo)
 [ -z "$NPROCS" ] && NPROCS=1
 make "-j$((NPROCS+1))" -s base && make -s install-base
 
diff --git a/vpnsetup_centos.sh b/vpnsetup_centos.sh
index c133bc4..8be592e 100755
--- a/vpnsetup_centos.sh
+++ b/vpnsetup_centos.sh
@@ -34,7 +34,7 @@ YOUR_PASSWORD=''
 # =====================================================
 
 export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-SYS_DT="$(date +%F-%T)"
+SYS_DT=$(date +%F-%T)
 
 exiterr()  { echo "Error: $1" >&2; exit 1; }
 exiterr2() { exiterr "'yum install' failed."; }
@@ -84,9 +84,9 @@ fi
 
 if [ -z "$VPN_IPSEC_PSK" ] && [ -z "$VPN_USER" ] && [ -z "$VPN_PASSWORD" ]; then
   bigecho "VPN credentials not set by user. Generating random PSK and password..."
-  VPN_IPSEC_PSK="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 20)"
+  VPN_IPSEC_PSK=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 20)
   VPN_USER=vpnuser
-  VPN_PASSWORD="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)"
+  VPN_PASSWORD=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)
 fi
 
 if [ -z "$VPN_IPSEC_PSK" ] || [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then
@@ -194,7 +194,7 @@ USE_DNSSEC = false
 USE_DH31 = false
 USE_GLIBC_KERN_FLIP_HEADERS = true
 EOF
-NPROCS="$(grep -c ^processor /proc/cpuinfo)"
+NPROCS=$(grep -c ^processor /proc/cpuinfo)
 [ -z "$NPROCS" ] && NPROCS=1
 make "-j$((NPROCS+1))" -s base && make -s install-base