If you're not using csh, then you can unsetenv for a single command:% DISPLAY= bk pull ...
Interactively, I use a csh with a leading t (everyone else does and there's a plethora of tcsh scripts which want to be `source`d, not forked, floating around here). Which is apparently enough of a csh for this to not work. I wonder if I could `alias bk DISPLAY= bk` in bash though.
But it's handy for system("...") calls, which use sh whether you like it or not.
