<assumptions>
 2 files x 65_000 lines x 60 fields x 8 chars = ~60MB data
 |-delimited ASCII
 search query is field 1
 data contains no 'escaped' |'s (e.g. \| or "xx|xx")
</assumptions>

##</code><code>##

[mk_ecl_index]
#!/usr/bin/perl
use DB_File;
for my $filename (@ARGV)
{

 my %ecl;
 tie %ecl, DB_File, "$filename.db"
  or die "Can't tie $filename.db: $!";
 open ASCII, "<$filename";
 while (<INPUT>)
 {
  chomp;
  next unless m{^ ([^\|]*
                     \|
                   [^\|]*)
                     \|}x; # first two fields
  # can't store refs in basic DB_File
  # but data guaranteed not to contain \n, so... :-/
  $ecl{$1} = ''
   unless defined $ecl{$1};
  $ecl{$1} .= $_ . "\n";
 }
 close ASCII;
 untie %ecl;
}

[grep_ecl]
#!/usr/bin/perl
# n.b. args opposite of Unix grep; filename, query, q2...
my $filename = shift;
my %index;
tie %index, DB_File, "$filename.db"
 or die "Can't tie to $filename.db: $!";
for my $query (@ARGV)
{
  if ( exists $index{$query} )
  {
    print $index{$query}; # newlines already provided
  } else {
    print STDERR "$0: $filename: $query not found\n";
  }
}
untie %index;