cnt=1; for i in $(fold -b1 inputfile);do
echo "Char # $cnt is $i"
cnt=$((cnt + 1)) 
done

cnt=1;while IFS= read -n1;do  
 echo "Char # $cnt is $REPLY"
 cnt=$((++cnt)) 
done<inputfile

#! /bin/ksh

typeset -L1 single
while read line
do
    while (( ${#line} > 0 ))
    do
        single="$line"
        # do what you like with $single
        echo $single
        line=${line#$single}
    done
done < input.txt

while read -n 1 ch; do echo "$ch" ; done < file