diff --git a/bashrc b/bashrc
index d7add76..ad4a2f1 100755
--- a/bashrc
+++ b/bashrc
@@ -55,6 +55,11 @@ export GIT_PAGER="less -F"
 export GIT_EDITOR="$EDITOR"
 echo "$TERM" | grep '^screen' >/dev/null 2>&1 || export TERM_ORIG=$TERM
 test "$TERM" = screen && test "$TERM_ORIG" = xterm-256color && TERM=screen-256color
+if test -n "$TMUX" && \
+    test -n "tmux display -p '#{client_termname}' | grep -o 256color"
+then
+    TERM=screen-256color
+fi
 
 test -z "$TMP" && export TMP=/tmp/${USER}-tmp
 mkdir -p "$TMP"
@@ -100,7 +105,7 @@ _timeformat_rfc2822="%a, %d %b %Y %T %z"
 
 alias ls="ls -hCF${_coloroption}${_timeoption}"
 # export GREP_OPTIONS=""
-alias gr="grep -n${_coloroption}"
+alias gr="grep -n --color=always"
 iswindows && alias grep="grep -n"
 # alias ll="ls -l"
 # alias la="ls -A"
diff --git a/tmux.conf b/tmux.conf
index 01bc6fe..9a59b80 100644
--- a/tmux.conf
+++ b/tmux.conf
@@ -38,3 +38,7 @@ setw -g window-status-current-attr bold
 
 set -g mode-bg white
 set -g mode-fg black
+
+# this does not work because it runs asyncly
+# if "test -n \"tmux display -p '#{client_termname}' | grep -o 256color\"" \
+#     "set -g default-terminal screen-256color" "set -g default-terminal screen"