cat chunk* > tmp.tmp
awk '   FILENAME=="string.txt" { arr[$0]=0 }
        FILENAME=="tmp.tmp"  { for(i=1; i<=NF; i++) {
             if ($i in arr) {arr[$i]++} 
        }}        
        END { for (i in arr) { print i, arr[i]}} ' string.txt tmp.tmp

#!/bin/bash -

# @(#) s3       Demonstrate string count total from files.

echo
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1) grep sort uniq
set -o nounset
echo

echo " strings file:"
cat strings

echo
echo " data files" data* ":"
cat -n data*

echo
echo " Results:"
grep -h -f strings data* |
sort |
uniq -c

exit 0

% ./s3

(Versions displayed with local utility "version")
Linux 2.6.11-x1
GNU bash 2.05b.0
grep (GNU grep) 2.5.1
sort (coreutils) 5.2.1
uniq (coreutils) 5.2.1

 strings file:
dog
horse
cat

 data files data1 data2 data3 data4 :
     1  File 1
     2  monkey
     3  cat
     4  dog
     5  dog
     6  File 2
     7  horse
     8  sawhorse
     9  Files 3
    10  cat
    11  horse
    12  witch
    13  seven
    14  File 4
    15  spider
    16  hoarse
    17  horse
    18  horse
    19  horse
    20  cat

 Results:
      3 cat
      2 dog
      5 horse
      1 sawhorse