datapump export to pipe

Env: Oracle EE 10.2.0.4 RH 4.6

I'm doing exports to a filesystem with limited space so want to compress the export on the fly, e.g.

.
.

cd $BACKUP_DIR
if [ ! -p $PIPE ] ; then

    mkfifo $PIPE
fi

echo "gzipping from $PIPE ..."
nohup gzip -c < $PIPE > ${DMPFILE}.gz &

echo "expdp started ..."
expdp $CREDENTIALS \

      DIRECTORY=DP_EXP_DIR \
      DUMPFILE=$PIPE \
      FULL=y \
      LOGFILE=$LOGFILE

BUT,.. as you may have guessed, my plan is flawed as expdp doesn't allow writing to a file that already exists, and of course the pipe must (exist that is)

Does anyone have a work around for this (that doesn't involve upgrading to 11g, buying new disks, exporting to a different dir)

Thanks in advance
Tony

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