diff --git a/common.sh b/common.sh
new file mode 100755
index 00000000..c7298ece
--- /dev/null
+++ b/common.sh
@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+
+[[ $DEBUG == true ]] && set -x
+
+log_info(){
+    >&2 echo "INFO>" $@
+}
+
+get_asn(){
+	local CONF_FILE=$1
+	unset PATTERN
+	unset COUNTRY
+	source $CONF_FILE
+	grep -P "${COUNTRY}\$" asnames.txt | 
+	grep -Pi "$PATTERN" | 
+	awk '{print $1}' | 
+	while read ASN; do 
+		ASN=${ASN#AS}
+		if grep '\.' <(echo $ASN) > /dev/null; then 
+			ASN_HIGH=${ASN%.*}
+			ASN_LOW=${ASN#*.}
+			ASN=$((ASN_HIGH * 65536 + ASN_LOW))
+		fi
+		echo $ASN
+	done
+}
+
+prepare_data(){
+	wget http://bgp.potaroo.net/as1221/asnames.txt -O asnames.txt
+	wget http://archive.routeviews.org/dnszones/rib.bz2 -O rib.bz2
+	log_info "runing bgpdump ..."
+	docker run -it --rm -v `pwd`:/bgpdump -w /bgpdump gaoyifan/bgpdump bgpdump -m -O rib.txt rib.bz2
+	log_info "done"
+}
diff --git a/generate.sh b/generate.sh
index 9a15e25c..00215e96 100755
--- a/generate.sh
+++ b/generate.sh
@@ -1,43 +1,14 @@
 #!/usr/bin/env bash
 
-if [[ -f /etc/kern_loader.conf ]]; then
-	alias grep='ggrep'
-fi
-
-get_asn(){
-	CONF_FILE=$1
-	unset PATTERN
-	unset COUNTRY
-	source $CONF_FILE
-	grep -P "${COUNTRY}\$" asnames.txt | 
-	grep -Pi "$PATTERN" | 
-	awk '{print $1}' | 
-	while read ASN; do 
-		ASN=${ASN#AS}
-		if grep '\.' <(echo $ASN) > /dev/null; then 
-			ASN_HIGH=${ASN%.*}
-			ASN_LOW=${ASN#*.}
-			ASN=$((ASN_HIGH * 65536 + ASN_LOW))
-		fi
-		echo $ASN
-	done
-}
-
-prepare_data(){
-	wget http://bgp.potaroo.net/as1221/asnames.txt
-	wget http://archive.routeviews.org/dnszones/rib.bz2
-	>&2 echo "runing bgpdump ..."
-	docker run -it --rm -v `pwd`:/bgpdump -w /bgpdump gaoyifan/bgpdump bgpdump -m -O rib.txt rib.bz2
-	>&2 echo "done"
-}
+source common.sh
 set -e
-[[ $DEBUG != true ]] && prepare_data
+[[ $SKIP_DATA_PREPARATION != true ]] && prepare_data
 mkdir -p result
-find operator -type f -name '*.conf' |
+ls operator/*.conf |
 while read file; do
 	operator=${file%.*}
 	operator=${operator##*/}
-	>&2 echo "generating IP list of $operator ..."
-	get_asn $file | xargs bgptools | docker run -i --rm gaoyifan/cidrmerge > result/$operator.txt
-	>&2 echo "done"
+	log_info "generating IP list of $operator ..."
+	get_asn $file | tee /dev/stderr | xargs bgptools | docker run -i --rm gaoyifan/cidrmerge > result/$operator.txt
+	log_info "done"
 done
diff --git a/stat.sh b/stat.sh
index 18ae16ec..c8d5b44b 100755
--- a/stat.sh
+++ b/stat.sh
@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 
+source common.sh
 cd result
 ls *.txt | 
 while read file; do