--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fa-extract-few.pl	Mon Feb 06 10:27:59 2017 -0500
@@ -0,0 +1,77 @@
+#!/usr/bin/perl -w
+use strict;
+use Bio::SeqIO;
+
+my(@Options, $verbose, $inverse, $file,$list,$exact);
+setOptions();
+
+my $in = Bio::SeqIO->new(-file=>$file, -format=>'Fasta');
+my $out = Bio::SeqIO->new(-fh=>\*STDOUT, -format=>'Fasta');
+my $nread=0;
+my $nwrote=0;
+
+my $pattern = join('|', @ARGV);
+
+if ( $list) {
+    my @list;
+    open my $in,'<',$list;
+    while ( <$in>) {
+        chomp;
+        push @list,$_;
+    }
+    close $in;
+    $pattern = join ('|',@list);
+}
+
+while (my $seq = $in->next_seq) {
+  $nread++;
+  my $match = ($seq->description =~ m/($pattern)/ or $seq->display_id =~ m/($pattern)/);
+  if ($exact) {
+	$match = ($seq->display_id =~ m/^($pattern)$/);
+  }
+  #print STDERR "Found match: ",$seq->display_id, " ", $seq->description, "\n" if $verbose;
+  if ($match ^ $inverse) {  # rare use for XOR !
+    $out->write_seq($seq);
+    $nwrote++;
+  }
+} 
+
+#print STDERR "Read $nread sequences, wrote $nwrote, with pattern: $pattern\n";
+exit(0);
+#----------------------------------------------------------------------
+# Option setting routines
+
+sub setOptions {
+  use Getopt::Long;
+
+  @Options = (
+    {OPT=>"h|help",    VAR=>\&usage,             DESC=>"This help"},
+    {OPT=>"verbose!",  VAR=>\$verbose, DEFAULT=>0, DESC=>"Verbose"},
+    {OPT=>"v|inverse!",  VAR=>\$inverse, DEFAULT=>0, DESC=>"Output NON-matching sequences instead"},
+    {OPT=>"f|file=s",   VAR=>\$file, DEFAULT=>"", DESC=>"The fasta file to extract sequences from"},
+    {OPT=>"exact",   VAR=>\$exact, DEFAULT=>"", DESC=>"Exact matches for display id only"},
+    {OPT=>"l|list=s",   VAR=>\$list, DEFAULT=>"", DESC=>"List of pattern to look from"},
+  );
+
+  (!@ARGV) && (usage());
+
+  &GetOptions(map {$_->{OPT}, $_->{VAR}} @Options) || usage();
+
+  # Now setup default values.
+  foreach (@Options) {
+    if (defined($_->{DEFAULT}) && !defined(${$_->{VAR}})) {
+      ${$_->{VAR}} = $_->{DEFAULT};
+    }
+  }
+}
+
+sub usage {
+  print "Usage: $0 [options] id1 [id2 ...] < input.fasta > output.fasta\n";
+  foreach (@Options) {
+    printf "  --%-13s %s%s.\n",$_->{OPT},$_->{DESC},
+           defined($_->{DEFAULT}) ? " (default '$_->{DEFAULT}')" : "";
+  }
+  exit(1);
+}
+ 
+#----------------------------------------------------------------------