diff --git a/INSTALL.sh b/INSTALL.sh
index cff67d5..1647b61 100755
--- a/INSTALL.sh
+++ b/INSTALL.sh
@@ -8,7 +8,7 @@ REVDEPD=/etc/revdep.d
 REVDEPCONF=/etc/revdep.conf
 
 mkdir -pv ${DESTDIR}{${BINDIR},${CONFDIR},${PORT_DIR},${REVDEPD}}
-install -m755 revdep pkgadd pkgdel pkgbuild pkgdeplist scratch updateconf ${DESTDIR}${BINDIR}
+install -m755 revdep pkgadd pkgdel pkgbuild scratch updateconf ${DESTDIR}${BINDIR}
 install -m644 scratchpkg.conf scratchpkg.repo ${DESTDIR}${CONFDIR}
 install -dm777 ${DESTDIR}${CACHE_DIR}/{packages,sources,log,work}
 install -m644 revdep.conf ${DESTDIR}${REVDEPCONF}
diff --git a/pkgbuild b/pkgbuild
index cee3c04..f918c69 100755
--- a/pkgbuild
+++ b/pkgbuild
@@ -35,10 +35,16 @@ msgwarn() {
 }
 
 updatemdsum() {
+	msg "Generating .checksums..."
+	generatemdsum > .checksums
+}
+
+generatemdsum() {
+	local um file missingsource
 	
 	if [ -z $source ]; then
-		msgwarn "source=() is empty, no need md5sum."
-		abort 0
+		echo SKIP > .checksums
+		return 0
 	fi
 		
 	for um in $(seq 0 $((${#source[@]} - 1))); do
@@ -68,46 +74,30 @@ updatemdsum() {
 		abort 1
 	fi
 	
-	echo -e "md5sum=($(md5sum $needupdatechecksum | awk '{ print $1 }'))"
+	md5sum $needupdatechecksum | sed -e 's|  .*/|  |' | sort -k 2
 		
 }
 
 checkmdsum() {
+	local mismatch m
 	
-	if [ -n "$source" ] && [ -z "$md5sum" ]; then
-		msgerr "md5sum=() is empty, please provide it."
-		abort 1
+	if [ ! -f .checksums ]; then
+		msg "Generating .checksums..."
+		generatemdsum > .checksums
+	else
+		generatemdsum > .checksums.tmp
+		mismatch=$(diff -w -t -U 0 .checksums .checksums.tmp | sed '/^---/d;/^+++/d;/^@@/d' | awk '{print $2}' | uniq)
 	fi
 	
-	if [ "${#source[@]}" != "${#md5sum[@]}" ]; then
-		msgerr "Total source and md5sums different."
-		abort 1
-	fi
+	rm -f .checksums.tmp
 	
-	for s in $(seq 0 $((${#source[@]} - 1))); do
-		if [ $(echo ${source[$s]} | grep -E "(ftp|http|https)://") ]; then
-			if [ $(echo ${source[$s]} | grep -E "::(ftp|http|https)://") ]; then
-				sourcename=$SOURCE_DIR/$(echo ${source[$s]} | awk -F '::' '{print $1}')
-			else
-				sourcename=$SOURCE_DIR/$(echo ${source[$s]} | rev | cut -d / -f 1 | rev)
-			fi
-		else
-			sourcename="${source[$s]}"
-		fi
-		sum=$(md5sum "$sourcename" | awk '{ print $1 }')
-		if [ "$sum" != "${md5sum[$s]}" ] && [ "SKIP" != "${md5sum[$s]}" ]; then
-			errormdsum+=($sourcename)
-		fi
-	done
-	
-	if [ "${#errormdsum[@]}" -gt 0 ]; then
+	if [ "$mismatch" ]; then
 		msgerr "md5sum mismatch:"
-		for mismatch in ${errormdsum[@]}; do
-			msg2 "$mismatch"
+		for m in $mismatch; do
+			msg2 $m
 		done
 		abort 1
-	fi
-	
+	fi	
 }
 
 download_src() {
@@ -157,8 +147,8 @@ download_src() {
 
 prepare_src() {
 	local FILE FILENAME SRC_DIR
-	
-	[ "$IGNORE_MDSUM" ] || checkmdsum
+	echo $CHECK_MDSUM
+	[ "$IGNORE_MDSUM" -o "$CHECK_MDSUM" = 0 ] || checkmdsum
 	
 	SRC=$WORK_DIR/$name/src
 	PKG=$WORK_DIR/$name/pkg
@@ -440,6 +430,8 @@ set_options() {
 			!buildflags) BUILD_FLAGS=0 ;;
 			makeflags)   MAKE_FLAGS=1 ;;
 			!makeflags)  MAKE_FLAGS=0 ;;
+			mdsum)       CHECK_MDSUM=1 ;;
+			!mdsum)      CHECK_MDSUM=0 ;;
 		esac
 	done
 }
@@ -653,7 +645,7 @@ main() {
 		abort 0
 	fi
 	
-	# calculate & print md5sum
+	# update md5sum
 	if [ "$UPDATE_MDSUM" ]; then
 		updatemdsum
 		abort 0
@@ -695,7 +687,7 @@ WORK_DIR="/var/cache/scratchpkg/work"
 DOWNLOAD_PROG="wget"
 COMPRESSION_MODE="xz"
 
-OPTIONS=(!libtool emptydirs strip zipman buildflags makeflags)
+OPTIONS=(!libtool emptydirs strip zipman buildflags makeflags checksum)
 
 INCLUDEINPKG=(install readme mkdirs)
 
diff --git a/pkgdeplist b/pkgdeplist
deleted file mode 100755
index 1de3b2c..0000000
--- a/pkgdeplist
+++ /dev/null
@@ -1,185 +0,0 @@
-#!/bin/bash
-#
-#  scratchpkg
-#
-#  Copyright (c) 2018 by Emmett1  (emmett1.2miligrams@gmail.com)
-#
-#  This program is free software: you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation, either version 3 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program.  If not, see <https://www.gnu.org/licenses/>.
-#
-
-INDEX_DIR="/var/lib/scratchpkg/index"
-REPO_FILE="/etc/scratchpkg.repo"
-
-msgerr() {
-	echo -e "==> ERROR: $1"
-}
-
-msginst() {
-	echo -e "[i] $1"
-}
-
-msgmiss() {
-	echo -e "[m] $1"
-}
-
-msgforeign() {
-	echo -e "[f] $1"
-}
-
-msgnoinst() {
-	echo -e "[-] $1"
-}
-
-checkdep() {
-	local depends
-	PORT_PATH=$(getportpath "$1")
-	if [ "$PORT_PATH" ]; then
-		depends=$(grep "^# depends[[:blank:]]*:" $PORT_PATH/spkgbuild | sed 's/^# depends[[:blank:]]*:[[:blank:]]*//' | tr ' ' '\n' | awk '!a[$0]++')
-		for dep in ${depends[@]}; do
-			echo $dep
-		done
-	else
-		return 0
-	fi
-}
-
-getportpath() {	
-	for repo in ${PORT_REPO[@]}; do
-		if [[ -f $repo/$1/spkgbuild ]]; then
-			dirname $repo/$1/spkgbuild
-			return 0
-		fi
-	done
-	return 1	
-}
-
-deplist() {	
-	# check currently process package for loop
-	if [ ${#CHECK[@]} -gt 0 ]; then
-		if [[ "$(echo ${CHECK[@]} | tr " " "\n" | grep -x $1)" == "$1" ]]; then
-			if [ "$IGNORE_LOOP" = 1 ]; then
-				return 0
-			else
-				msgerr "loop dependency found: $1"
-				exit 1
-			fi
-		fi
-	fi
-	
-	# add package to currently process
-	CHECK+=($1)
-	
-	# check dependencies
-	for i in $(checkdep $1); do
-		[ -e $INDEX_DIR/$i/.pkginfo ] && [ "$QUICK" ] && continue
-		if [[ $(echo ${DEP[@]} | tr " " "\n" | grep -x $i) = "" ]]; then
-			deplist $i
-		fi
-	done
-	
-	# add dependency to list checked dep
-	if [[ $(echo ${DEP[@]} | tr " " "\n" | grep -x $1) = "" ]]; then
-		DEP+=($1)
-	fi
-	
-	# delete process package array
-	for i in "${!CHECK[@]}"; do
-		if [[ ${CHECK[i]} = "$1" ]]; then
-			unset 'CHECK[i]'
-		fi
-	done	
-}
-
-usage() {
-	cat << EOF
-Usage:
-  $(basename $0) [ <options> <packages> ]
-
-Options:
-  -q, --quick              calculate only not-installed package/dependency
-  -i, --installed          print only installed package/dependency
-  -n, --not-installed      print only not-installed package/dependency
-  -m, --missing            print only missing package/dependency
-  -f, --foreign            print foreign package/dependency
-  -l, --loop               ignore loop dependencies
-  -h, --help               print this help message
-   
-EOF
-}
-
-while [ "$1" ]; do
-	case $1 in
-		-q|--quick)         QUICK=1 ;;
-		-i|--installed)     INSTALLED=1 ;;
-		-n|--not-installed) NOT_INSTALLED=1 ;;
-		-m|--missing)       MISSING=1 ;;
-		-f|--foreign)       FOREIGN=1 ;;
-		-l|--loop)          IGNORE_LOOP=1 ;;
-		-h|--help)          USAGE=1 ;;
-		-*)                 msgerr "Invalid option. ($1)"; exit 1 ;;
-		*)                  PKG+=($1) ;;
-	esac
-	shift
-done
-
-if [ "$USAGE" = 1 ]; then
-	usage
-	exit 0
-fi
-
-if [ ! -f "$REPO_FILE" ]; then
-	msgerr "repo file not exist. ($REPO_FILE)"
-	exit 1
-fi
-
-if [ "${#PKG[@]}" = 0 ]; then
-	msgerr "Please specify package name to list its dependencies order."
-	exit 1
-fi
-
-while read -r repodir repourl junk; do
-	case $repodir in
-		""|"#"*) continue ;;
-	esac
-	PORT_REPO+=($repodir)
-done < "$REPO_FILE"
-
-# set all to 1 (all) if not use any of it
-if [ ! "$INSTALLED" ] && [ ! "$NOT_INSTALLED" ] && [ ! "$MISSING" ] && [ ! "$FOREIGN" ]; then
-	INSTALLED=1
-	NOT_INSTALLED=1
-	MISSING=1
-	FOREIGN=1
-fi
-
-# calculate dependencies
-for pkg in ${PKG[@]}; do
-	deplist $pkg
-done
-
-for deps in ${DEP[@]}; do
-	if [ -e $INDEX_DIR/$deps/.pkginfo ]; then
-		if [ ! $(getportpath "$deps") ]; then
-			[ "$FOREIGN" ] && msgforeign "$deps"  # print foreign pkg
-		else
-			[ "$INSTALLED" ] && msginst "$deps"   # print installed
-		fi
-	elif [ ! $(getportpath "$deps") ]; then
-		[ "$MISSING" ] && msgmiss "$deps"         # print missing port
-	else
-		[ "$NOT_INSTALLED" ] && msgnoinst "$deps" # print not installed
-	fi
-done
-
-exit 0
diff --git a/scratchpkg.conf b/scratchpkg.conf
index ee94490..a50e0fd 100644
--- a/scratchpkg.conf
+++ b/scratchpkg.conf
@@ -24,8 +24,9 @@ MAKEFLAGS="-j$(nproc)"
 # -- zipman:      Compress manual (man and info) pages in MAN_DIRS with gzip
 # -- buildflags:  Enable buildflags (CFLAGS and CXXFLAGS)
 # -- makeflags:   Enable makeflags (MAKEFLAGS)
+# -- checksum:    Enable checking checksum
 #
 # -- These are default values for the options=() settings
 # -- add '!' in front of this option to disable it
 #
-# OPTIONS=(!libtool emptydirs strip zipman buildflags makeflags)
+# OPTIONS=(!libtool emptydirs strip zipman buildflags makeflags checksum)