#! /bin/bash 

for i in {1..4}; 
    do 
        touch "${i}_file.txt"
    done

for i in {1..3};
    do 
        touch "image_${i}.jpg"
    done

echo "Creating files ... "
sleep 0.5

ls -l 
echo "files creation completed! "

###############################

read -p "enter j or t: " choice
while [ $choice != "j" -a $choice != "t" ];
do
    echo "wrong letter, retry: "
    read choice 
done

read -p "write prefix to add to these files: " prefix
echo "the prefix is $prefix "

if [ "$choice" == "t" ]; then 
    for element in *.txt
    do 
        # echo "txt files are: ${element}"
        mv ${element} ${prefix}${element}
    done 
#else 
elif [ "$choice" == "j" ]; then
    for element in *.jpg
    do 
        mv ${element} ${prefix}${element}
    done
fi