I often have multiple sessions running at any given time. This sometimes leads to issues when trying to reconstruct work using history. As a result, I was thinking it would be useful to include the $BASHPID somehow so that I could sort by shell and then time. My naive attempt at this was to try

```
export HISTTIMEFORMAT="$BASHPID %Y %m %d - %H:%M:%S| "

```

But all this does is add the current shell's $BASHPID to the output of 'history'.

A search for HISTTIMEFORMAT and $BASHPID returned nothing. ANy suggestions on how to get this kind of behavior?