How to write shell script,to automate file conversion?

I have 30 files(ascii),which I want convert to binary.Linux command line(FORTRAN 77 CODE) that has been compiled

./rec_binary 

Relevant part of the code

      character*72 ifname,ofname
c
      write(*, fmt="(/'Enter input file name')")
      read(5,85) ifname
85    format(a72)
      write(*, fmt="(/'Enter output file name')")
      read(5,85) ofname

Then code asks for input and output file names

Enter input file name
rec01.txt

Enter output file name
rec.01

How to automate this?I have tried like this

#!/bin/csh -f
set list = 'ls rec*.txt'
foreach file ($list)
rec_binary ${file} > 

Or

#!/bin/sh
for f in .txt
do
./rec_binary F
done

But I do not have a clue for next step.Text files are

rec01.txt
rec02.txt

rec30.txt

Output files

rec.01
rec.02

rec.30

Answer

Try this:

#!/bin/bash
for each in `ls rec*.txt`
do
  op_file=$(echo $each | sed 's/(rec)([0-9]*).txt/1.2/')
  ./rec_binary <<EOF
$each
$op_file
EOF
done

The variable op_file converts your rec01.txt to rec.01.