+ vtHeadZero=$(vtfile_head_zero $vtfile)
+ if [ $vtHeadZero -gt 0 ]; then
+ vtdump=$(hexdump -s $vtHeadZero -n 512 -e '512/1 "%02X"' $vtfile)
+ vtmagic=$(echo $vtdump | sed 's/^\(00\)*//')
+ let vtoffset="(${#vtdump}-${#vtmagic})/2+$vtHeadZero"
+ echo "skip head $vtHeadZero zeros with magic ${vtmagic:0:4}" >> $VTLOG
+ else
+ echo "terminate with all zero data file" >> $VTLOG
+ break
+ fi