for file in *;
     do
        if  [ $file=[$.sff]] ; then
          mkdir ${$file/.sff/""/}
          mv $file ${file/.sff/""/}/
            fi
        for $file in $file/
              do { ......
            }
done

die() { echo "$*" >&2; exit 1; }
for file in *; do
  dir=${file%.*}
  test -d $dir || mkdir $dir  # or just mkdir -p $dir
  test -f $dir && die "$dir exists and is a file!"
  mv $file $dir
done
for dir in *; do ...; done  # Do something in each directory

for file in *.*
do
  dir=${file%.*}
  mkdir "$dir"
  newfile=$dir/$file
  mv "$file" "$newfile"
  ... do something with "$newfile"
done