BR0200.aaa.tsv
BR0200.bbb.tsv
BR0200.ccc.tsv
BR0210.aaa.tsv
BR0210.bbb.tsv
BR0210.ccc.tsv
W0210.aaa.tsv
W0210.aaa.tsv
W0210.aaa.tsv

BR0200
BR210
W0210

#!/bin/bash

for file in BR* W0*; do
dir = "${file%%.*}"
if [-e $dir];then
mv "$file" "$dir"
else
mkdir -p "$dir"
mv "$file" "$dir"
fi
done

dir="${file%%.*}"

if [ -e $dir ]; then
    ^       ^

for file in {BR,W0}*.*; do
    dir=${file%%.*}
    mkdir -p "$dir"
    mv "$file" "$dir"
done