Shell Programming and Scripting

awk 'NR==FNR{p=$0;next}
{r=FS=$0;$0=p;printf "%s=%d\n",r,NF-1}' file1 file2

% cat file1              
ACFCFACCACARCSHFARCVJVASTVAJFTVAJVGHBAJ
% cat file2              
A
C
F
R
% awk 'NR==FNR{p=$0;next}
{r=FS=$0;$0=p;printf "%s=%d\n",r,NF-1}' file1 file2
A=9
C=7
F=4
R=2

#!/bin/zsh

# @(#) s2       Demonstrate small optimization, avoid repeated reads.

FILE=${1-data1}

echo
echo " Input $FILE:"
cat $FILE

# <data2 while read;do printf "%s=%d\n" "$REPLY" "${#$(<data1)//[^$REPLY]}";done

echo
echo " Results:"
t1=$(<$FILE)
while read
do
  printf "%s=%d\n" "$REPLY" "${#${t1//[^$REPLY]}}"
done <data2

exit 0

% ./s2

 Input data1:
ACFCFACCACARCSHFARCVJVASTVAJFTVAJVGHBAJ

 Results:
A=9
C=7
F=4
R=2

sed '/^$/d' b > tb
sed '/^$/d' a > ta
awk '{
if (length($1)>3)
for (i=1;i<=length($1);i++)
arr[substr($1,i,1)]++
else
print $1" = "arr[$1]
}
' tb ta
rm tb ta