diff --git a/script/_confirmation.sh b/script/_confirmation.sh
new file mode 100644
index 0000000..edb0c40
--- /dev/null
+++ b/script/_confirmation.sh
@@ -0,0 +1,87 @@
+# ******************************************************************************* 
+#                        Confirmation and Passphrase setting 
+# ******************************************************************************* 
+
+# Sanity check for volume group name
+if echo ${VGNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume group name.
+	cat <<HEREDOC 1>&2
+***** ERROR : VGNAME is "${VGNAME}" *****
+THe "-" is not allowed in the volume name. 
+Check passphrase and config.txt
+
+Installation terminated.
+HEREDOC
+		return
+fi # "-" is found in the volume group name.
+
+# Sanity check for root volume name
+if echo ${LVROOTNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume name.
+	cat <<HEREDOC 1>&2
+***** ERROR : LVROOTNAME is "${LVROOTNAME}" *****
+THe "-" is not allowed in the volume name. 
+Check passphrase and config.txt
+
+Installation terminated.
+HEREDOC
+		return
+fi # "-" is found in the volume name.
+
+# Sanity check for swap volume name
+if echo ${LVSWAPNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume name.
+	cat <<HEREDOC 1>&2
+***** ERROR : LVSWAPNAME is "${LVSWAPNAME}" *****
+THe "-" is not allowed in the volume name. 
+Check passphrase and config.txt
+
+Installation terminated.
+HEREDOC
+		return
+fi # "-" is found in the volume name.
+
+# For surre ask the config.sh is edited
+cat <<HEREDOC
+
+The destination logical volume label is "${LVROOTNAME}"
+"${LVROOTNAME}" uses ${LVROOTSIZE} of the LVM volume group.
+Are you ready to install? [Y/N]
+HEREDOC
+read YESNO
+if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
+	cat <<HEREDOC 1>&2
+
+Installation terminated.
+HEREDOC
+	return
+fi	# if YES
+
+# For sure ask ready to erase. 
+if [ ${ERASEALL} -eq 1 ] ; then
+	echo "Are you sure you want to erase entire ${DEV}? [Y/N]"
+	read YESNO
+	if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
+		cat <<HEREDOC 1>&2
+Check config.sh. The variable ERASEALL is ${ERASEALL}.
+
+Installation terminated.
+HEREDOC
+		return
+	fi	# if YES
+fi	# if erase all
+
+# ----- Set Passphrase -----
+# Input passphrase
+echo "Type passphrase for the disk encryption."
+read -sr PASSPHRASE
+export PASSPHRASE
+
+echo "Type passphrase again, to confirm."
+read -sr PASSPHRASE_C
+
+# Validate whether both are indentical or not
+if [ ${PASSPHRASE} != ${PASSPHRASE_C} ] ; then
+	cat <<HEREDOC 1>&2
+***** ERROR : Passphrase doesn't match *****
+Installation terminated.
+HEREDOC
+	return
+fi	# passphrase validation
diff --git a/script/_parainstall.sh b/script/_parainstall.sh
new file mode 100644
index 0000000..d6969ac
--- /dev/null
+++ b/script/_parainstall.sh
@@ -0,0 +1,43 @@
+# ******************************************************************************* 
+#                        Common part of para-install 
+# ******************************************************************************* 
+
+# Record the PID of the installer. 
+installer_pid=$!
+
+# While the /etc/default/grub in the install target is NOT existing, keep sleeping.
+# If installer terminated without file copy, this script also terminates.
+while [ ! -e ${TARGETMOUNTPOINT}/etc/default/grub ]
+do
+	sleep 1 # 1sec.
+
+	 # Check if installer still exist
+	if ! ps $installer_pid  > /dev/null ; then	# If not exists
+	cat <<HEREDOC 1>&2
+The installer terminated unexpectedly. 
+
+Installation process terminated.
+HEREDOC
+	return
+
+	fi
+done # while
+
+# Perhaps, too neuvous. Wait 1 more sectond to avoid the rece condition.
+sleep 1 # 1sec.
+
+# Make target GRUB aware to the crypt partition
+# This must do it after start of the file copy by installer, but before the end of the file copy.
+# If the environment is not GUI, keep quiet not to bother the TUI installer. 
+if [ $GUIENV -eq 1 ]; then
+	echo "...Add GRUB_ENABLE_CRYPTODISK entry to ${TARGETMOUNTPOINT}/etc/default/grub "
+fi
+echo "GRUB_ENABLE_CRYPTODISK=y" >> ${TARGETMOUNTPOINT}/etc/default/grub
+
+
+# And then, wait for the end of installer process
+# If the environment is not GUI, keep quiet not to bother the TUI installer. 
+if [ $GUIENV -eq 1 ]; then
+	echo "...Waiting for the end of GUI/TUI installer."
+fi
+wait $installer_pid
diff --git a/script/_parainstall_msg.sh b/script/_parainstall_msg.sh
new file mode 100644
index 0000000..4f910d1
--- /dev/null
+++ b/script/_parainstall_msg.sh
@@ -0,0 +1,24 @@
+cat <<HEREDOC
+******************************************************************************
+The pre-install process is done. We are ready to install the Linux to the 
+target storage device. By pressing return key, GUI/TUI installer starts.
+
+Please pay attention to the partition/logical volume mapping configuration. 
+In this installation, you have to map the previously created partitions/logical
+volumes to the appropriate directories of the target system as followings :
+
+HEREDOC
+
+# In the EFI system, add this mapping
+if [  ${ISEFI} -eq 1 ] ; then
+	echo "/boot/efi        : ${DEV}${EFIPARTITION}"
+fi
+
+# Root volume mapping
+echo "/                : /dev/mapper/${VGNAME}-${LVROOTNAME}"
+
+# In case of erased storage, add this mapping
+if [ ${ERASEALL} -eq 1 ] ; then
+	echo "swap             : /dev/mapper/${VGNAME}-${LVSWAPNAME}"
+fi
+
diff --git a/script/_preinstall.sh b/script/_preinstall.sh
new file mode 100644
index 0000000..e80c56b
--- /dev/null
+++ b/script/_preinstall.sh
@@ -0,0 +1,88 @@
+# ******************************************************************************* 
+#                                Pre-install stage 
+# ******************************************************************************* 
+
+
+# ----- Erase entire disk, create partitions, format them  and encrypt the LUKS partition -----
+if [ ${ERASEALL} -eq 1 ] ; then
+
+	# Assign specified space and rest of disk to the EFI and LUKS partition, respectively.
+	if [  ${ISEFI} -eq 1 ] ; then
+		# Zap existing partition table and create new GPT
+		echo "...Initialize ${DEV} with GPT."
+		sgdisk --zap-all "${DEV}"
+		# Create EFI partition and format it
+		echo "...Create an EFI partition on ${DEV}."
+		sgdisk --new=${EFIPARTITION}:0:+${EFISIZE} --change-name=${EFIPARTITION}:"EFI System"  --typecode=${EFIPARTITION}:ef00 "${DEV}"  
+		echo "...Format the EFI parttion."
+		mkfs.vfat -F 32 -n EFI-SP "${DEV}${EFIPARTITION}"
+		# Create Linux partition
+		echo "...Create a Linux partition on ${DEV}."
+		sgdisk --new=${CRYPTPARTITION}:0:0    --change-name=${CRYPTPARTITION}:"Linux LUKS" --typecode=${CRYPTPARTITION}:8309 "${DEV}"
+		# Then print them
+		sgdisk --print "${DEV}"
+	else
+		# Zap existing partition table
+		echo "...Erase partition table of ${DEV}."
+		dd if=/dev/zero of=${DEV} bs=512 count=1
+		# Create MBR and allocate max storage for Linux partition
+		echo "...Create a Linux partition on ${DEV} with MBR."
+		sfdisk ${DEV} <<HEREDOC
+2M,,L
+HEREDOC
+	fi	# if EFI firmware
+
+	# Encrypt the partition to install Linux
+	echo "...Initialize ${DEV}${CRYPTPARTITION} as crypt partition"
+	printf %s "${PASSPHRASE}" | cryptsetup luksFormat --type=luks1 --key-file - --batch-mode "${DEV}${CRYPTPARTITION}"
+
+fi	# if erase all
+
+# ----- Open the LUKS partition -----
+# Open the crypt partition. 
+echo "...Open a crypt partition ${DEV}${CRYPTPARTITION} as \"${CRYPTPARTNAME}\""
+printf %s "${PASSPHRASE}" | cryptsetup open -d - "${DEV}${CRYPTPARTITION}" ${CRYPTPARTNAME}
+
+# Check whether successful open. If mapped, it is successful. 
+if [ ! -e /dev/mapper/${CRYPTPARTNAME} ] ; then 
+	cat <<HEREDOC 1>&2
+***** ERROR : Cannot open LUKS volume "${CRYPTPARTNAME}" on ${DEV}${CRYPTPARTITION}. *****
+Check passphrase and config.txt
+
+Installation terminated.
+HEREDOC
+	return
+fi	# if crypt volume is unable to open
+
+# ----- Configure the LVM in LUKS volume -----
+# Check volume group ${VGNAME} exist or not
+if  vgdisplay -s ${VGNAME} &> /dev/null ; then		# if exist
+	echo "...Volume group ${VGNAME} already exist. Skipped to create. No problem."
+else
+	echo "...Initialize a physical volume on \"${CRYPTPARTNAME}\""
+	pvcreate /dev/mapper/${CRYPTPARTNAME}
+	echo "...And then create Volume group \"${VGNAME}\"."
+	vgcreate ${VGNAME} /dev/mapper/${CRYPTPARTNAME}
+fi # if /dev/volume-groupt exist
+
+# Create a SWAP Logical Volume on VG, if it doesn't exist
+if [ -e /dev/mapper/${VGNAME}-${LVSWAPNAME} ] ; then 
+	echo "...Swap volume already exist. Skipped to create. No problem."
+else
+	echo "...Create logical volume \"${LVSWAPNAME}\" on \"${VGNAME}\"."
+	lvcreate -L ${LVSWAPSIZE} -n ${LVSWAPNAME} ${VGNAME} 
+fi	# if /dev/mapper/swap volume already exit. 
+
+# Create a ROOT Logical Volume on VG. 
+if [ -e /dev/mapper/${VGNAME}-${LVROOTNAME} ] ; then 
+	cat <<HEREDOC 1>&2
+***** ERROR : Logical volume "${VGNAME}-${LVROOTNAME}" already exists. *****
+Check LVROOTNAME environment variable in config.txt.
+
+Installation terminated.
+HEREDOC
+	return
+else
+	echo "...Create logical volume \"${LVROOTNAME}\" on \"${VGNAME}\"."
+	lvcreate -l ${LVROOTSIZE} -n ${LVROOTNAME} ${VGNAME}
+fi	# if the root volun already exist
diff --git a/script/ubuntu-kaiten-yaki.sh b/script/ubuntu-kaiten-yaki.sh
index 7d5085c..56ade88 100644
--- a/script/ubuntu-kaiten-yaki.sh
+++ b/script/ubuntu-kaiten-yaki.sh
@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# Load configuration parameter
+source config.sh
+
 # Varidate whether script is executed as sourced or not
 (return 0 2>/dev/null) && sourced=1 || sourced=0
 if [ $sourced -eq 0 ] ; then
@@ -13,12 +16,9 @@ HEREDOC
 	exit    # use "exit" instead of "return", if not "sourced" execusion
 fi # "sourced" validation
 
-# Load configuration parameter
-source config.sh
-
-# ******************************************************************************* 
-#                        Confirmation and Passphrase setting 
-# ******************************************************************************* 
+# This is the mount point of the install target. 
+# Refered in the para-install stage
+export TARGETMOUNTPOINT="/target"
 
 # Distribution check
 if ! uname -a | grep ubuntu -i > /dev/null  ; then	# "Ubuntu" is not found in the OS name.
@@ -40,210 +40,28 @@ HEREDOC
 
 fi # "Ubuntu" is not found in the OS name.
 
-# Sanity check for volume group name
-
-if echo ${VGNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume group name.
-	cat <<HEREDOC 1>&2
-***** ERROR : VGNAME is "${VGNAME}" *****
-THe "-" is not allowed in the volume name. 
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-		return
-fi # "-" is found in the volume group name.
-
-# Sanity check for root volume name
-
-if echo ${LVROOTNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume name.
-	cat <<HEREDOC 1>&2
-***** ERROR : LVROOTNAME is "${LVROOTNAME}" *****
-THe "-" is not allowed in the volume name. 
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-		return
-fi # "-" is found in the volume name.
-
-# Sanity check for swap volume name
-if echo ${LVSWAPNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume name.
-	cat <<HEREDOC 1>&2
-***** ERROR : LVSWAPNAME is "${LVSWAPNAME}" *****
-THe "-" is not allowed in the volume name. 
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-		return
-fi # "-" is found in the volume name.
-
-# For surre ask the config.sh is edited
-cat <<HEREDOC
-
-The destination logical volume label is "${LVROOTNAME}"
-"${LVROOTNAME}" uses ${LVROOTSIZE} of the LVM volume group.
-Are you ready to install? [Y/N]
-HEREDOC
-read YESNO
-if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
-	cat <<HEREDOC 1>&2
-
-Installation terminated.
-HEREDOC
-	return
-fi	# if YES
-
-# For sure ask ready to erase. 
-if [ ${ERASEALL} -eq 1 ] ; then
-	echo "Are you sure you want to erase entire ${DEV}? [Y/N]"
-	read YESNO
-	if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
-		cat <<HEREDOC 1>&2
-Check config.sh. The variable ERASEALL is ${ERASEALL}.
-
-Installation terminated.
-HEREDOC
-		return
-	fi	# if YES
-fi	# if erase all
-
-# ----- Set Passphrase -----
-# Input passphrase
-echo "Type passphrase for the disk encryption."
-read -sr PASSPHRASE
-export PASSPHRASE
-
-echo "Type passphrase again, to confirm."
-read -sr PASSPHRASE_C
-
-# Validate whether both are indentical or not
-if [ ${PASSPHRASE} != ${PASSPHRASE_C} ] ; then
-	cat <<HEREDOC 1>&2
-***** ERROR : Passphrase doesn't match *****
-Installation terminated.
-HEREDOC
-	return
-fi	# passphrase validation
+# ******************************************************************************* 
+#                                Confirmation before installation 
+# ******************************************************************************* 
 
+# Common part of the parameter confirmation
+source _confirmation.sh
 
 # ******************************************************************************* 
 #                                Pre-install stage 
 # ******************************************************************************* 
 
-
-# ----- Erase entire disk, create partitions, format them  and encrypt the LUKS partition -----
-if [ ${ERASEALL} -eq 1 ] ; then
-
-	# Assign specified space and rest of disk to the EFI and LUKS partition, respectively.
-	if [  ${ISEFI} -eq 1 ] ; then
-		# Zap existing partition table and create new GPT
-		echo "...Initialize ${DEV} with GPT."
-		sgdisk --zap-all "${DEV}"
-		# Create EFI partition and format it
-		echo "...Create an EFI partition on ${DEV}."
-		sgdisk --new=${EFIPARTITION}:0:+${EFISIZE} --change-name=${EFIPARTITION}:"EFI System"  --typecode=${EFIPARTITION}:ef00 "${DEV}"  
-		echo "...Format the EFI parttion."
-		mkfs.vfat -F 32 -n EFI-SP "${DEV}${EFIPARTITION}"
-		# Create Linux partition
-		echo "...Create a Linux partition on ${DEV}."
-		sgdisk --new=${CRYPTPARTITION}:0:0    --change-name=${CRYPTPARTITION}:"Linux LUKS" --typecode=${CRYPTPARTITION}:8309 "${DEV}"
-		# Then print them
-		sgdisk --print "${DEV}"
-	else
-		# Zap existing partition table
-		echo "...Erase partition table of ${DEV}."
-		dd if=/dev/zero of=${DEV} bs=512 count=1
-		# Create MBR and allocate max storage for Linux partition
-		echo "...Create a Linux partition on ${DEV} with MBR."
-		sfdisk ${DEV} <<HEREDOC
-2M,,L
-HEREDOC
-	fi	# if EFI firmware
-
-	# Encrypt the partition to install Linux
-	echo "...Initialize ${DEV}${CRYPTPARTITION} as crypt partition"
-	printf %s "${PASSPHRASE}" | cryptsetup luksFormat --type=luks1 --key-file - --batch-mode "${DEV}${CRYPTPARTITION}"
-
-fi	# if erase all
-
-# ----- Open the LUKS partition -----
-# Open the crypt partition. 
-echo "...Open a crypt partition ${DEV}${CRYPTPARTITION} as \"${CRYPTPARTNAME}\""
-printf %s "${PASSPHRASE}" | cryptsetup open -d - "${DEV}${CRYPTPARTITION}" ${CRYPTPARTNAME}
-
-# Check whether successful open. If mapped, it is successful. 
-if [ ! -e /dev/mapper/${CRYPTPARTNAME} ] ; then 
-	cat <<HEREDOC 1>&2
-***** ERROR : Cannot open LUKS volume "${CRYPTPARTNAME}" on ${DEV}${CRYPTPARTITION}. *****
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-	return
-fi	# if crypt volume is unable to open
-
-# ----- Configure the LVM in LUKS volume -----
-# Check volume group ${VGNAME} exist or not
-if  vgdisplay -s ${VGNAME} &> /dev/null ; then		#  exist ?
-	echo "...Volume group ${VGNAME} already exist. Skipped to create. No problem."
-else
-	echo "...Initialize a physical volume on \"${CRYPTPARTNAME}\""
-	pvcreate /dev/mapper/${CRYPTPARTNAME}
-	echo "...And then create Volume group \"${VGNAME}\"."
-	vgcreate ${VGNAME} /dev/mapper/${CRYPTPARTNAME}
-fi # if /dev/volume-groupt exist
-
-# Create a SWAP Logical Volume on VG, if it doesn't exist
-if [ -e /dev/mapper/${VGNAME}-${LVSWAPNAME} ] ; then 
-	echo "...Swap volume already exist. Skipped to create. No problem."
-else
-	echo "...Create logical volume \"${LVSWAPNAME}\" on \"${VGNAME}\"."
-	lvcreate -L ${LVSWAPSIZE} -n ${LVSWAPNAME} ${VGNAME} 
-fi	# if /dev/mapper/swap volume already exit. 
-
-# Create a ROOT Logical Volume on VG. 
-if [ -e /dev/mapper/${VGNAME}-${LVROOTNAME} ] ; then 
-	cat <<HEREDOC 1>&2
-***** ERROR : Logical volume "${VGNAME}-${LVROOTNAME}" already exists. *****
-Check LVROOTNAME environment variable in config.txt.
-
-Installation terminated.
-HEREDOC
-	return
-else
-	echo "...Create logical volume \"${LVROOTNAME}\" on \"${VGNAME}\"."
-	lvcreate -l ${LVROOTSIZE} -n ${LVROOTNAME} ${VGNAME}
-fi	# if the root volun already exist
+# Common part of the pre-install stage
+source _preinstall.sh
 
 # ******************************************************************************* 
 #                                Para-install stage 
 # ******************************************************************************* 
-cat <<HEREDOC
-******************************************************************************
-The pre-install process is done. We are ready to install the Linux to the 
-target storage device. By pressing return key, Ubuntu Ubiquity installer 
-starts.
 
-Please pay attention to the partition/logical volume mapping configuration. 
-In this installation, you have to map the previously created partitions/logical
-volumes to the appropriate directories of the target system as followings :
-
-HEREDOC
-
-# In the EFI system, add this mapping
-if [  ${ISEFI} -eq 1 ] ; then
-	echo "/boot/efi        : ${DEV}${EFIPARTITION}"
-fi
-
-# Root volume mapping
-echo "/                : /dev/mapper/${VGNAME}-${LVROOTNAME}"
-
-# In case of erased storage, add this mapping
-if [ ${ERASEALL} -eq 1 ] ; then
-	echo "swap             : /dev/mapper/${VGNAME}-${LVSWAPNAME}"
-fi
+# Show common message to let the operator focus on the critical part
+source _parainstall_msg.sh
 
+# Ubuntu dependent message
 cat <<HEREDOC
 
 ************************ CAUTION! CAUTION! CAUTION! ****************************
@@ -257,41 +75,13 @@ HEREDOC
 # waitfor a console input
 read dummy_var
 
-# Start GUI installer 
+# Start Ubiquity installer 
 ubiquity &
-# Record the PID
-ubiquity_pid=$!
 
-# While the /etc/default/grub in the install target is NOT existing, keep sleeping.
-# If ubiquity terminated without file copy, this script also terminates.
-while [ ! -e /target/etc/default/grub ]
-do
-	sleep 1 # 1sec.
-
-	 # Check if installer still exist
-	if ! ps $ubiquity_pid  > /dev/null ; then	# If not exists
-	cat <<HEREDOC 1>&2
-The ubiquity installer terminated unexpectedly. 
-
-Installation process terminated.
-HEREDOC
-	return
-
-	fi
-done # while
-
-# Perhaps, too neuvous. Wait 1 more sectond to avoid the rece condition.
-sleep 1 # 1sec.
-
-# Make target GRUB aware to the crypt partition
-# This must do it after start of the file copy by ubiquity, but before the end of the file copy.
-echo "...Add GRUB_ENABLE_CRYPTODISK entry to /target/etc/default/grub "
-echo "GRUB_ENABLE_CRYPTODISK=y" >> /target/etc/default/grub
-
-
-# And then, wait for the end of Ubiquity process
-echo "...Waiting for the end of Ubiquity installer."
-wait $ubiquity_pid
+# Common part of the para-install. 
+# Record the install PID, modify the /etc/default/grub of the target, 
+# and then, wait for the end of sintaller. 
+source _parainstall.sh
 
 # ******************************************************************************* 
 #                                Post-install stage 
diff --git a/script/void-kaiten-yaki.sh b/script/void-kaiten-yaki.sh
index 3952626..2cbf3eb 100644
--- a/script/void-kaiten-yaki.sh
+++ b/script/void-kaiten-yaki.sh
@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# Load configuration parameter
+source config.sh
+
 # Varidate whether script is executed as sourced or not
 (return 0 2>/dev/null) && sourced=1 || sourced=0
 if [ $sourced -eq 0 ] ; then
@@ -13,12 +16,9 @@ HEREDOC
 	exit    # use "exit" instead of "return", if not "sourced" execusion
 fi # "sourced" validation
 
-# Load configuration parameter
-source config.sh
-
-# ******************************************************************************* 
-#                        Confirmation and Passphrase setting 
-# ******************************************************************************* 
+# This is the mount point of the install target. 
+# Refered in the para-install stage
+export TARGETMOUNTPOINT="/mnt/target"
 
 # Distribution check
 if ! uname -a | grep void -i > /dev/null ; then	# "Void" is not found in the OS name.
@@ -40,186 +40,19 @@ HEREDOC
 
 fi # "Void" is not found in the OS name.
 
-# Sanity check for volume group name
-if echo ${VGNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume group name.
-	cat <<HEREDOC 1>&2
-***** ERROR : VGNAME is "${VGNAME}" *****
-THe "-" is not allowed in the volume name. 
-Check passphrase and config.txt
+# ******************************************************************************* 
+#                                Confirmation before installation 
+# ******************************************************************************* 
 
-Installation terminated.
-HEREDOC
-		return
-fi # "-" is found in the volume group name.
-
-# Sanity check for root volume name
-if echo ${LVROOTNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume name.
-	cat <<HEREDOC 1>&2
-***** ERROR : LVROOTNAME is "${LVROOTNAME}" *****
-THe "-" is not allowed in the volume name. 
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-		return
-fi # "-" is found in the volume name.
-
-# Sanity check for swap volume name
-
-if echo ${LVSWAPNAME} | grep "-" -i > /dev/null ; then	# "-" is found in the volume name.
-	cat <<HEREDOC 1>&2
-***** ERROR : LVSWAPNAME is "${LVSWAPNAME}" *****
-THe "-" is not allowed in the volume name. 
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-		return
-fi # "-" is found in the volume name.
-
-# For surre ask the config.sh is edited
-cat <<HEREDOC
-
-The destination logical volume label is "${LVROOTNAME}"
-"${LVROOTNAME}" uses ${LVROOTSIZE} of the LVM volume group.
-Are you ready to install? [Y/N]
-HEREDOC
-read YESNO
-if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
-	cat <<HEREDOC 1>&2
-
-Installation terminated.
-HEREDOC
-	return
-fi	# if YES
-
-# For sure ask ready to erase. 
-if [ ${ERASEALL} -eq 1 ] ; then
-	echo "Are you sure you want to erase entire ${DEV}? [Y/N]"
-	read YESNO
-	if [ ${YESNO} != "Y" -a ${YESNO} != "y" ] ; then
-		cat <<HEREDOC 1>&2
-Check config.sh. The variable ERASEALL is ${ERASEALL}.
-
-Installation terminated.
-HEREDOC
-		return
-	fi	# if YES
-fi	# if erase all
-
-# ----- Set Passphrase -----
-# Input passphrase
-echo "Type passphrase for the disk encryption."
-read -sr PASSPHRASE
-export PASSPHRASE
-
-echo "Type passphrase again, to confirm."
-read -sr PASSPHRASE_C
-
-# Validate whether both are indentical or not
-if [ ${PASSPHRASE} != ${PASSPHRASE_C} ] ; then
-	cat <<HEREDOC 1>&2
-***** ERROR : Passphrase doesn't match *****
-Installation terminated.
-HEREDOC
-	return
-fi	# passphrase validation
-
-# Install essential packages.
-if [ ${GUIENV} -eq 1 ] ; then  
-	xbps-install -y -Su xbps gptfdisk xterm
-else
-	xbps-install -y -Su xbps gptfdisk
-fi
+# Common part of the parameter confirmation
+source _confirmation.sh
 
 # ******************************************************************************* 
 #                                Pre-install stage 
 # ******************************************************************************* 
 
-
-# ----- Erase entire disk, create partitions, format them  and encrypt the LUKS partition -----
-if [ ${ERASEALL} -eq 1 ] ; then
-
-	# Assign specified space and rest of disk to the EFI and LUKS partition, respectively.
-	if [  ${ISEFI} -eq 1 ] ; then
-		# Zap existing partition table and create new GPT
-		echo "...Initialize ${DEV} with GPT."
-		sgdisk --zap-all "${DEV}"
-		# Create EFI partition and format it
-		echo "...Create an EFI partition on ${DEV}."
-		sgdisk --new=${EFIPARTITION}:0:+${EFISIZE} --change-name=${EFIPARTITION}:"EFI System"  --typecode=${EFIPARTITION}:ef00 "${DEV}"  
-		echo "...Format the EFI parttion."
-		mkfs.vfat -F 32 -n EFI-SP "${DEV}${EFIPARTITION}"
-		# Create Linux partition
-		echo "...Create a Linux partition on ${DEV}."
-		sgdisk --new=${CRYPTPARTITION}:0:0    --change-name=${CRYPTPARTITION}:"Linux LUKS" --typecode=${CRYPTPARTITION}:8309 "${DEV}"
-		# Then print them
-		sgdisk --print "${DEV}"
-	else
-		# Zap existing partition table
-		echo "...Erase partition table of ${DEV}."
-		dd if=/dev/zero of=${DEV} bs=512 count=1
-		# Create MBR and allocate max storage for Linux partition
-		echo "...Create a Linux partition on ${DEV} with MBR."
-		sfdisk ${DEV} <<HEREDOC
-2M,,L
-HEREDOC
-	fi	# if EFI firmware
-
-	# Encrypt the partition to install Linux
-	echo "...Initialize ${DEV}${CRYPTPARTITION} as crypt partition"
-	printf %s "${PASSPHRASE}" | cryptsetup luksFormat --type=luks1 --key-file - --batch-mode "${DEV}${CRYPTPARTITION}"
-
-fi	# if erase all
-
-# ----- Open the LUKS partition -----
-# Open the crypt partition. 
-echo "...Open a crypt partition ${DEV}${CRYPTPARTITION} as \"${CRYPTPARTNAME}\""
-printf %s "${PASSPHRASE}" | cryptsetup open -d - "${DEV}${CRYPTPARTITION}" ${CRYPTPARTNAME}
-
-# Check whether successful open. If mapped, it is successful. 
-if [ ! -e /dev/mapper/${CRYPTPARTNAME} ] ; then 
-	cat <<HEREDOC 1>&2
-***** ERROR : Cannot open LUKS volume "${CRYPTPARTNAME}" on ${DEV}${CRYPTPARTITION}. *****
-Check passphrase and config.txt
-
-Installation terminated.
-HEREDOC
-	return
-fi	# if crypt volume is unable to open
-
-# ----- Configure the LVM in LUKS volume -----
-# Check volume group ${VGNAME} exist or not
-if  vgdisplay -s ${VGNAME} &> /dev/null ; then		# if exist
-	echo "...Volume group ${VGNAME} already exist. Skipped to create. No problem."
-else
-	echo "...Initialize a physical volume on \"${CRYPTPARTNAME}\""
-	pvcreate /dev/mapper/${CRYPTPARTNAME}
-	echo "...And then create Volume group \"${VGNAME}\"."
-	vgcreate ${VGNAME} /dev/mapper/${CRYPTPARTNAME}
-fi # if /dev/volume-groupt  exist
-
-# Create a SWAP Logical Volume on VG, if it doesn't exist
-if [ -e /dev/mapper/${VGNAME}-${LVSWAPNAME} ] ; then 
-	echo "...Swap volume already exist. Skipped to create. No problem."
-else
-	echo "...Create logical volume \"${LVSWAPNAME}\" on \"${VGNAME}\"."
-	lvcreate -L ${LVSWAPSIZE} -n ${LVSWAPNAME} ${VGNAME} 
-fi	# if /dev/mapper/swap volume already exit. 
-
-# Create a ROOT Logical Volume on VG. 
-if [ -e /dev/mapper/${VGNAME}-${LVROOTNAME} ] ; then 
-	cat <<HEREDOC 1>&2
-***** ERROR : Logical volume "${VGNAME}-${LVROOTNAME}" already exists. *****
-Check LVROOTNAME environment variable in config.txt.
-
-Installation terminated.
-HEREDOC
-	return
-else
-	echo "...Create logical volume \"${LVROOTNAME}\" on \"${VGNAME}\"."
-	lvcreate -l ${LVROOTSIZE} -n ${LVROOTNAME} ${VGNAME}
-fi	# if the root volun already exist
+# Common part of the pre-install stage
+source _preinstall.sh
 
 # ADD "rd.auto=1 cryptdevice=/dev/sda2:${LUKS_NAME} root=/dev/mapper/${VGNAME}-${ROOTNAME}" to GRUB.
 # This is magical part. I have not understood why this is required. 
@@ -231,31 +64,11 @@ sed -i "s#loglevel=4#loglevel=4 rd.auto=1 cryptdevice=/dev/sda2:${LUKS_NAME} roo
 # ******************************************************************************* 
 #                                Para-install stage 
 # ******************************************************************************* 
-cat <<HEREDOC
-******************************************************************************
-The pre-install process is done. We are ready to install the Linux to the 
-target storage device. By pressing return key,  void-installer 
-starts.
 
-Please pay attention to the partition/logical volume mapping configuration. 
-In this installation, you have to map the previously created partitions/logical
-volumes to the appropriate directories of the target system as followings :
-
-HEREDOC
-
-# In the EFI system, add this mapping
-if [  ${ISEFI} -eq 1 ] ; then
-	echo "/boot/efi        : ${DEV}${EFIPARTITION}"
-fi
-
-# Root volume mapping
-echo "/                : /dev/mapper/${VGNAME}-${LVROOTNAME}"
-
-# In case of erased storage, add this mapping
-if [ ${ERASEALL} -eq 1 ] ; then
-	echo "swap             : /dev/mapper/${VGNAME}-${LVSWAPNAME}"
-fi
+# Show common message to let the operator focus on the critical part
+source _parainstall_msg.sh
 
+# Ubuntu dependent message
 cat <<HEREDOC
 
 ************************ CAUTION! CAUTION! CAUTION! ****************************
@@ -269,51 +82,17 @@ HEREDOC
 # waitfor a console input
 read dummy_var
 
-# Start TUI installer 
+# Start void-installer 
 if [ $GUIENV -eq 1 ]; then
 	xterm -fa monospace -fs ${XTERMFONTSIZE} -e void-installer &
 else
 	void-installer &
 fi
-# Record the PID
-voidinstaller_pid=$!
 
-# While the /etc/default/grub in the install target is NOT existing, keep sleeping.
-# If void-installer terminated without file copy, this script also terminates.
-while [ ! -e /mnt/target/etc/default/grub ]
-do
-	sleep 1 # 1sec.
-
-	# Chcheck if installer still exist
-	if ! ps $voidinstaller_pid  > /dev/null   ; then	# If not exists
-	cat <<HEREDOC 1>&2
-The void-installer terminated unexpectedly. 
-
-Installation process terminated.
-HEREDOC
-	return
-
-	fi
-done # while
-
-# Perhaps, too neuvous. Wait 1 more sectond to avoid the rece condition.
-sleep 1 # 1sec.
-
-# Make target GRUB aware to the crypt partition
-# This must do it after start of the file copy by void-installer, but before the end of the file copy.
-# If the environment is not GUI, keep quiet not to bother the TUI installer. 
-if [ $GUIENV -eq 1 ]; then
-	echo "...Add GRUB_ENABLE_CRYPTODISK entry to /mnt/target/etc/default/grub "
-fi
-echo "GRUB_ENABLE_CRYPTODISK=y" >> /mnt/target/etc/default/grub
-
-
-# And then, wait for the end of void-installer process
-# If the environment is not GUI, keep quiet not to bother the TUI installer. 
-if [ $GUIENV -eq 1 ]; then
-	echo "...Waiting for the end of void-installer."
-fi
-wait $voidinstaller_pid
+# Common part of the para-install. 
+# Record the install PID, modify the /etc/default/grub of the target, 
+# and then, wait for the end of sintaller. 
+source _parainstall.sh
 
 # ******************************************************************************* 
 #                                Post-install stage