trap DEBUG and $_

[Dan Stromberg]

Is there a way of outputting a datestamp to shell stderr at the _beginning_ of the execution of a command, that won't wipe out $_?

I use $_ quite a bit for the last argument to the previous command, interactively.  And I'd like to datestamp all my commands. Datestamping after with $PS1 is easy, but datestamping before is a little harder.

I've tried using:

   function preexec { if tty -s; then echo "$(tput smso)cmd started $(date +%Y\ %a\ %b\ %d\ %r)$(tput rmso)"; fi; }

   trap preexec DEBUG

...but as you might suspect, I'm finding that $_ is always "preexec" with this enabled.

Any suggestions?

Thanks!