Bash input for multiple file

Question

I have thousands of two set of files one with name.ext and another files name ending with name.ext.in, so for every name.ext there is a name.ext.in and now i have to pass this a

Answer 1

I guess the simplest form is

    for f in "*.ext"
    do                 
         customise.pl  $f.ext $f.ext.in      
    done

OUTPUT: