--- a/setup	Mon Oct 31 11:54:49 2011 +0700
+++ b/setup	Tue Nov 01 22:40:21 2011 +0700
@@ -44,17 +44,22 @@
 }
 
 _rc() {
+  if test -z "${3}" || test -z "${2}" || test -z "${1}"; then
+    _echo "Invalid command."
+    return
+  fi
   _srcfile="${rcdir}/${2}"
   _dstfile="${HOME}/${3}"
   if test ! -h "${_dstfile}"; then
     if test -f "${_dstfile}"; then
       cp "${_dstfile}" "${_dstfile}.bak"
+      _echo "${_dstfile} backed up to ${_dstfile}.bak"
     elif test -d "${_dstfile}"; then
       cp -r "${_dstfile}" "${_dstfile}.bak"
+      _echo "Directory ${_dstfile} backed up to ${_dstfile}.bak"
     fi
-    _echo "${_dstfile} backed up to ${_dstfile}.bak"
   fi
-  rm -f "${_dstfile}"
+  rm -rf "${_dstfile}"
   case "${1}" in
     install)
       ln -fs "${_srcfile}" "${_dstfile}"