diff --git a/.zshrc2 b/.zshrc2
index 3b66101..9b2f4be 100644
--- a/.zshrc2
+++ b/.zshrc2
@@ -16,6 +16,7 @@ export GPG_TTY=$(tty)
 export LESS_TERMCAP_md=$'\E[01;33m'
 # env for dfs
 if [[ -f ~/.config/dotfiles/env ]]; then set -a; source ~/.config/dotfiles/env; set +a; fi
+export DFS_OS_TYPE="$("$DOTFILES/tools/common.sh" get_os_type)"
 
 # antigen
 if [[ "$DFS_NO_WALL" == "1" ]]; then
@@ -104,7 +105,8 @@ alias "se"='sudo -sE'
 alias "sl"='sudo zsh -l'
 alias "cps"='rsync -avh --info=progress2'
 alias "mvs"='rsync -avh --info=progress2 --remove-source-files'
-if [[ $("$DOTFILES/tools/common.sh" get_os_type) == "linux" ]]; then alias "ping"='ping -n'; alias "ping6"='ping6 -n'; fi
+if [[ "$DFS_OS_TYPE" == "linux" ]]; then alias "ping"='ping -n'; alias "ping6"='ping6 -n'; fi
+if [[ "$DFS_OS_TYPE" == "msys" ]]; then alias "tmux"='script -qO /dev/null -c "tmux -u"'; fi
 alias "pbd"='ping baidu.com'
 alias "p114"='ping 114.114.114.114'
 alias "p666"='ping6 2001:da8::666'
diff --git a/tools/common.sh b/tools/common.sh
index 2705aca..ad62ae7 100755
--- a/tools/common.sh
+++ b/tools/common.sh
@@ -190,6 +190,7 @@ apost_beacon()
 
 get_os_type()
 {
+    test -z "$DFS_OS_TYPE" || ( echo "$DFS_OS_TYPE"; return )
     local ans="unknown"
     case "$(uname -s)" in
         Darwin*)    ans="MacOS";;
@@ -198,11 +199,13 @@ get_os_type()
         Linux* )    ans="Linux";;
         *)          ans="unknown";;
     esac
+    export DFS_OS_TYPE="$ans"
     echo $ans | tr '[:upper:]' '[:lower:]'
 }
 
 get_linux_dist()
 {
+    test -z "$DFS_LINUX_DIST" || ( echo "$DFS_LINUX_DIST"; return )
     local ans="unknown"
     if [ -f /etc/os-release ]; then
         . /etc/os-release
@@ -221,6 +224,7 @@ get_linux_dist()
     else
         ans="unknown"
     fi
+    export DFS_LINUX_DIST="$ans"
     echo $ans | tr '[:upper:]' '[:lower:]'
 }