Crunch customized password list

hey guys ive been trying to make a custom password list but ive been having some problems..
lets suppose in need to make a password list containing only passwords in the format of 3 numbers 2 letters and 3 numbers
123XX123
i first thought a simple bash script could do it:

#!/bin/bash
for i in a b c d e f
do
for x in a b c d e f
do
echo "$i $x"
./crunch 5 5 -f charset.lst numeric -o /home/bunk3r/Desktop/tk1000PASS.txt -t @@@$i$x
done
done

now the echo command does print all letters but crunch is not taking the values fromn the for loop, my output shows a list containing only the passwords for the last letter of the list in tis case f......i made a similar script in python and i get the same results any suggestions??

Code:

---

#!/bin/bash
for i in a b c d e f
do
for x in a b c d e f
do
echo "$i $x"
./crunch 5 5 -f charset.lst numeric -o /home/bunk3r/Desktop/tk1000PASS.txt -t @@@$i$x
done
done

---

This script is so ugly!
But I'll use your own script. :)

Code:

---

#!/bin/bash
for i in a b c d e f
do
for x in a b c d e f
do
echo $i $x
/pentest/passwords/crunch/crunch 8 8 -f charset.lst numeric -t @@@$i$x@@@
done
done

---

Regards,

crunch 8 8 -t %%%@@%%%
will generate
000aa000
through
999zz999

if you only want a-f
crunch 8 8 abcdef -t %%%@@%%%