diff --git a/run.sh b/run.sh
index 2d5f026..6c3bf34 100755
--- a/run.sh
+++ b/run.sh
@@ -1,5 +1,5 @@
-#! /bin/bash
+#!/bin/sh
 
-BASEDIR=$(dirname $0)
+BASEDIR="$(dirname $(realpath $(readlink -f $0)))"
 
 $BASEDIR/latest/chrome --user-data-dir="$BASEDIR/user-data-dir" $* &> /dev/null &
diff --git a/update-and-run.sh b/update-and-run.sh
index 93673ed..cbff49e 100755
--- a/update-and-run.sh
+++ b/update-and-run.sh
@@ -1,3 +1,5 @@
-#! /bin/bash
-cd $(dirname $0)
-./update.sh && ./run.sh
+#!/bin/sh
+
+BASEDIR="$(dirname $(realpath $(readlink -f $0)))"
+
+$BASEDIR/update.sh && $BASEDIR/run.sh
diff --git a/update.sh b/update.sh
index 6730185..a6cb36c 100755
--- a/update.sh
+++ b/update.sh
@@ -1,31 +1,61 @@
-#! /bin/bash
-
-cd $(dirname $0)
+#!/bin/sh
+
+BASEDIR="$(dirname $(realpath $(readlink -f $0)))"
+
+web() {
+local list="wget curl"
+for item in $list;
+do
+    if [ -z $(command -v $item) ]; then
+        echo $list | sed "s/$item//g"
+    fi
+done
+}
+
+dl() {
+case $(web) in
+    *wget*) wget -q --show-progress -O $@;;
+    *curl*) curl -#L -o $@;;
+esac
+}
+
+out() {
+case $(web) in
+    *curl*) curl -sL $@;;
+    *wget*) wget -qO - $@;;
+esac
+}
+
+TRUNK="snapshots"
+if [ -n "$1" ]; then
+OPT="$1"
+shift
+case "$OPT" in
+    snapshots|s) TRUNK="snapshots";;
+    continuous|c) TRUNK="continuous";;
+esac
+fi
 
-LASTCHANGE_URL="https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/Linux_x64%2FLAST_CHANGE?alt=media"
+LASTCHANGE_URL="https://www.googleapis.com/download/storage/v1/b/chromium-browser-$TRUNK/o/Linux_x64%2FLAST_CHANGE?alt=media"
 
-REVISION=$(curl -s -S $LASTCHANGE_URL)
+REVISION=$(out $LASTCHANGE_URL)
 
 echo "latest revision is $REVISION"
 
-if [ -d $REVISION ] ; then
+if [ -d $BASEDIR/$REVISION ] ; then
   echo "already have latest version"
   exit
 fi
 
-ZIP_URL="https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/Linux_x64%2F$REVISION%2Fchrome-linux.zip?alt=media"
+ZIP_URL="https://www.googleapis.com/download/storage/v1/b/chromium-browser-$TRUNK/o/Linux_x64%2F$REVISION%2Fchrome-linux.zip?alt=media"
 
-ZIP_FILE="${REVISION}-chrome-linux.zip"
+ZIP_FILE="chrome-linux-${REVISION}.zip"
 
 echo "fetching $ZIP_URL"
 
-rm -rf $REVISION
-mkdir $REVISION
-pushd $REVISION
-curl -# $ZIP_URL > $ZIP_FILE
+dl "$BASEDIR/$ZIP_FILE" "$ZIP_URL"
 echo "unzipping.."
-unzip $ZIP_FILE
-popd
-rm -f ./latest
-ln -s $REVISION/chrome-linux/ ./latest
-
+unzip "$BASEDIR/$ZIP_FILE" -d "$BASEDIR"
+mv "$BASEDIR/chrome-linux" "$BASEDIR/$REVISION"
+rm -f "$BASEDIR/latest" "$BASEDIR/$ZIP_FILE"
+ln -s "$BASEDIR/$REVISION" "$BASEDIR/latest"