ls with numeric range doesn't work inside bash script

Question

I have a folder with files named as file_1.ext...file_90.ext. I can list a range of them with the following command:

$ ls /home/rasoul/myfolder/         


        

Answer 1

Brace expansion happens before variable expansion.

(Moreover, don't parse ls output.). You could instead say:

for f in $(seq $st $ed); do 
    echo "${DIR}/file_${f}.ext";
done