prepare for temporary bashrc with tmux

bashrc_add

@@ -16,6 +16,8 @@
 # https://guide.bash.academy/expansions/
 # https://www.tldp.org/LDP/abs/html/refcards.html#AEN22473
 if [[ $- = *i* ]] ; then
+    if [ "${BASHRC_TMP:-x}" == "x" ]
+    then
         #echo "interactive shell" >&2
 
         # define variables
@@ -227,5 +229,8 @@ EOF
             logdebug "started tmux"
         fi
         logdebug "after"
+    else
+        exec bash --rcfile "${BASHRC_TMP}"
+    fi
 
 fi