Converting in batch into 8 unsigned bit format using GDAL?

Could you please correct my batch command?

I had 100 img images which need to be converted into 8 unsigned bit format for further use in TIMESAT.

mkdir test for %%f in (*.img) do gdal_translate -of ENVI -scale -1 1 1 255 -a_nodata 0 -co INTERLEAVE=BSQ "%%f" test/%%f.dat