diff --git a/setup.sh b/setup.sh
index 9083e6e..31a3a85 100755
--- a/setup.sh
+++ b/setup.sh
@@ -22,6 +22,7 @@ gen_common(){
     __iswindows=false
     __isdarwin=false
     __islinux=false
+    # $OSTYPE is another choice. which is better?
     case `uname` in
         (MINGW*) __ismsys=true ;;
         (CYGWIN*) __iscygwin=true ;;
diff --git a/shrc b/shrc
index e3c82d0..6130c3a 100755
--- a/shrc
+++ b/shrc
@@ -329,7 +329,14 @@ __safe_alias pc="sudo \paco -D"
 alias pycalc="python -i -c 'from math import *' "
 __safe_alias py3=python3
 __safe_alias py2=python2
-alias _reloadrc="exec \"$SHELL\""
+# SHELL cannot be used. for example, run bash inside zsh, SHELL is set to be
+# /bin/zsh
+if $inbash
+then
+    alias _reloadrc="exec bash"
+elif $inzsh
+    alias _reloadrc="exec zsh"
+fi
 # alias mytime="date +%Y%m%d-%H%M%S"
 alias sh="ENV=$HOME/.shrc PS1=\$\  PROMPT_COMMAND="" sh"
 # type trash >/dev/null 2>&1 && alias rm=trash