Double do while loop (BASH)

I am trying to make the following double do while boucle:

#!/bin/bash

#Router cisco
ls equipos/ |grep cisco |tr ' ' '\n' >> $$.cisco.tmp

config="/Users/joseluis/Desktop/prueba/config"

echo "XXXXXXXXXX ficheros"
echo $$.cisco.tmp
echo $config
echo "XXXXXXXXXX contenido tmp"
cat $$.cisco.tmp
echo "XXXXXXXXXX contenido config"
cat $config
echo "XXXXXXXXXX"


while IFS= read -r router
do
    echo "LOOP"
    echo $router

    echo "equipos/$router"

    while IFS= read -r config
    do

        grep "$config" "equipos/$router" &> /dev/null

            if [ $? == "1" ]; then
                echo "$router -> $config"
            fi  
    echo "---"
    echo "$config"
    echo "---"


    done <"$config"

done <"$$.cisco.tmp"

rm $$.cisco.tmp

$ ./script.sh 
XXXXXXXXXX ficheros
7405.cisco.tmp
/Users/joseluis/Desktop/prueba/config
XXXXXXXXXX contenido tmp
cisco.1
cisco.2
XXXXXXXXXX contenido config
a
1
XXXXXXXXXX
LOOP
cisco.1
equipos/cisco.1
---
a
---
cisco.1 -> 1
---
1
---
LOOP
cisco.2
equipos/cisco.2
./script.sh: line 41: : No such file or directory

But when i tried to evaluate the second condition i receive the "No such file or directory" error, but that is no true, the file exists. Why i receive this error? Can somebody help me?

Thank you.

BR.