Rename files consecutively

file_rename.sh

count=1

if [ ! -d "temp1" ];then mkdir temp1; fi

for i in *;
do
        if [ -f "$i" ];
        then
                ext=$(echo "$i" | awk -F"." '{print $NF}')
                mv "$i" "temp1/img_$count.$ext";
                count=$(expr $count + 1)
        fi  
done

mv temp1/* .
rm -r temp1