# declare our vars
my (%codes, @array_codes);

#undef input record sep to get all data at once
local $/;

# make an array of codes by splitting DATA on whitespace
@array_codes = split /\s+/, <DATA>;

# map the codes to a hash, counting duplicates
# using a for loop for efficiency
foreach $code_key (@array_codes) {
   $codes{$code_key}++;
} 

# print it out
printf "$_\t$codes{$_}\n" for keys %codes;


__DATA__
baaba ba abab abab abab baaba baaba babaa. 
abab aaba ba abab ba. bababab abab abab ba aaba. 
ba bababab aaba abab babaa baaba ba baaba. 
aaba ba bababab ba bababab abab ba aaba abab baaba abab. 
ba abab abab ba.