-------------- create.pl --------------
#!/usr/bin/perl

use GDBM_File;
use Fcntl;

open( myfile, "term_doc_freq.out" ) or die;

my $lineNo;
my %wordInDoc = ();

tie (%wordInDoc, GDBM_File, "TermFreqDocid.db", O_CREAT|O_RDWR, 0644) || die ("Cannot create or open phone.db");

while( <myfile> )
{
my($line) = $_;
chomp $line;
$lineNo++;

@document = split (/ /, $line);
$docID = $lineNo;

foreach $term (@document) {
$wordInDoc{$term}{$docID}=0;
}
foreach $term (@document) {
++$wordInDoc{$term}{$docID};
}
}

untie (%wordInDoc);
exit;

-------------- read.pl --------------
#!/usr/bin/perl

use GDBM_File;
use Fcntl;

tie (%TermDocFreqHash, GDBM_File, "TermFreqDocid.db", O_RDONLY, 0777) ||
die ("Cannot open TermFreqDocid.db");

foreach $term ( sort( keys %TermDocFreqHash ) )
{
print $term." ";
my %tmp = $TermDocFreqHash{$term};

foreach $docID ( keys %tmp ) {
print $TermDocFreqHash{$term}{$docID};
}
}

untie (%TermDocFreqHash);
exit;