userout option
The userout option specifies a tabbed text output file with field names specified by the -userfields option. For example, the following will give the same output as -blast6out hits.m8:
usearch -ublast reads.fastq -db proteins.fa -evalue 0.01 -userout hits.m8
-userfields query+target+id+alnlen+mism+opens+qlo+qhi+tlo+thi+evalue+bits