# Most efficient way to test & mkdir :0 ihc * ! ? test -d $DIR |mkdir -p $DIR
:0 wic # if needed, create today's ackdir; add sender * $ ! TESTNAME ?? ^^$ACKS/fullacks/ | test -d $ACKS/$DATE || mkdir $ACKS/$DATE ;\
I'd say the efficiency is the same. Both versions run the external program test, and mkdir if the test fails. The w flag in the second probably doesn't do anything, it's only relevant with f. My guess :-) Volker