Update bash to latest tmux environment on reattaching.

tmup

#!/bin/bash

tmup () 
{ 
    echo -n "Updating to latest tmux environment...";
    export IFS=",";
    for line in $(tmux showenv -t $(tmux display -p "#S") | tr "\n" ",");
    do
        if [[ $line == -* ]]; then
            unset $(echo $line | cut -c2-);
        else
            export $line;
        fi;
    done;
    unset IFS;
    echo "Done"
}

showenv has a -s option now to format the output as bourne shell commands, so I think eval $(tmux showenv -s ...) should do the job of this script now.