diff --git a/install.sh b/install.sh
index 925873e..6429b2c 100755
--- a/install.sh
+++ b/install.sh
@@ -149,7 +149,8 @@ uninstall_symlink()
     done
 }
 
-install_crontab(){
+install_crontab()
+{
     if [[ -x $(command -v crontab) ]]; then
         fmt_note "installing \"$CRON_JOB\" to crontab ..."
         ( crontab -l | grep -vxF "${CRON_JOB}" | grep -v "no crontab for"; echo "$CRON_JOB" ) | crontab -
@@ -158,7 +159,8 @@ install_crontab(){
     fi
 }
 
-uninstall_crontab(){
+uninstall_crontab()
+{
     if [[ -x $(command -v crontab) ]]; then
         fmt_note "removing \"$CRON_JOB\" from crontab ..."
         ( crontab -l | grep -vxF "$CRON_JOB" ) | crontab -
@@ -167,7 +169,8 @@ uninstall_crontab(){
     fi
 }
 
-install_tmux_tpm(){
+install_tmux_tpm()
+{
     TMUX_TPM="$HOME/.tmux/plugins/tpm"
     if [[ -x $(command -v tmux) && ! -d "$TMUX_TPM" ]]; then
         fmt_note "installing tmux tpm ..."
@@ -186,7 +189,8 @@ install_tmux_tpm(){
     fi
 }
 
-install_vim_vundle(){
+install_vim_vundle()
+{
     VIM_VUNDLE="$HOME/.vim/bundle/Vundle.vim"
     if [[ -x $(command -v vim) && ! -d "$VIM_VUNDLE" ]]; then
         fmt_note "installing vim vundle ..."
@@ -196,7 +200,8 @@ install_vim_vundle(){
     fi
 }
 
-install_update(){
+install_update()
+{
     fmt_note "installing update.sh ..."
     cp "${DOTFILES}/.update.sh" "${DOTFILES}/update.sh"
     chmod +x "${DOTFILES}/update.sh"
@@ -208,12 +213,14 @@ install_update(){
     fi
 }
 
-uninstall_update(){
+uninstall_update()
+{
     fmt_note "removing update.sh ..."
     rm "${DOTFILES}/update.sh"
 }
 
-install(){
+install()
+{
     if [[ "$INSTALL_DEP" == "1" ]]; then install_dependencies; fi
     install_update
     preinstall_check
@@ -227,7 +234,8 @@ install(){
     fmt_note "done installing!"
 }
 
-uninstall(){
+uninstall()
+{
     ask_for_yN "do you really want to uninstall?"
     if [[ $? != 1 ]]; then
         fmt_error "aborting this job ..."
diff --git a/tools/alpine.sh b/tools/alpine.sh
index 59d81c2..57f9b2e 100755
--- a/tools/alpine.sh
+++ b/tools/alpine.sh
@@ -1,20 +1,19 @@
 #!/bin/bash
-
 set -e
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]:-${(%):-%x}}" )" && pwd )
+source "$THIS_DIR/common.sh"
 
 set_mirror()
 {
     MIRROR=${1:-"mirrors.tuna.tsinghua.edu.cn"}
-    sed -i "s@dl-cdn.alpinelinux.org@$MIRROR@g" /etc/apk/repositories
+    sed -i "s@dl-cdn.alpinelinux.org@${MIRROR}@g" /etc/apk/repositories
 }
 
 apk_add()
 {
     apk update
-
     # lite
     apk add zsh bash git tmux vim curl fzf iputils coreutils util-linux
-
     # full
     if [[ -z "$DFS_LITE" ]]; then
         apk add wget python3 py3-pip htop gcc g++ cmake make perl linux-headers bind-tools man-db
diff --git a/tools/macos.sh b/tools/macos.sh
index ff4e566..fca9e2a 100755
--- a/tools/macos.sh
+++ b/tools/macos.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
-
 set -e
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]:-${(%):-%x}}" )" && pwd )
+source "$THIS_DIR/common.sh"
 
 brew_install()
 {
diff --git a/tools/msys2.sh b/tools/msys2.sh
index 00ed05d..350a789 100755
--- a/tools/msys2.sh
+++ b/tools/msys2.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
-
 set -e
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]:-${(%):-%x}}" )" && pwd )
+source "$THIS_DIR/common.sh"
 
 set_mirror()
 {
diff --git a/tools/ubuntu.sh b/tools/ubuntu.sh
index ef753e4..88917b6 100755
--- a/tools/ubuntu.sh
+++ b/tools/ubuntu.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
-
 set -e
+THIS_DIR=$( cd "$( dirname "${BASH_SOURCE[0]:-${(%):-%x}}" )" && pwd )
+source "$THIS_DIR/common.sh"
 
 set_mirror()
 {
@@ -12,10 +13,8 @@ set_mirror()
 apt_install()
 {
     apt-get update -y
-
     # lite
-    apt-get install -y git zsh bash tmux vim curl inetutils-ping less bsdmainutils ca-certificates
-
+    apt-get install -y git zsh bash tmux vim curl inetutils-ping less bsdmainutils
     # full
     if [[ -z "$DFS_LITE" ]]; then
         apt-get install wget dialog net-tools dnsutils netcat traceroute sudo python3 python3-pip cron openssh-client openssh-server htop gcc g++ cmake make zip