sub findtext
{
    my ($files, $terms) = @_;
    my @filenames;
    for my $arg ( @$files ) {
        push @filenames, grep /\w/, split( /\W+/, $arg );
    }
    my %target;
    $target{$_} = undef for @$terms;

    local $/ = undef;  # this only applies within the sub

    for my $file ( @filenames )
    {
        unless ( open( FILE, "/home/jroberts/$file.txt" )) {
            warn "open failed on $file: $!";
            next;
        }
        $_ = <FILE>;  # read full text;
        close FILE;

        my @words = split;  # @words has all words in $file
        for ( @words ) {
            s{(.*)}{<B>$1</B>} if ( exists( $target{$_} ));
        }

        # all target words in $file are now marked, so
        # print the sequences that contain marked words

        my $printing = 0;
        for my $i ( 0 .. $#words )
        {
            if ( $words[$i] =~ /<B>/ ) {
                if ( $i and $printing == 0 ) {   # backtrack for prior context
                    my $j = ( $i >= 6 ) ? $i - 6 : 0;
                    print join " ", @words[$j..$i-1];
                }
                print $word[$i]; # (update: have to print this every time)
                $printing = 6;  # number of following words to print
            }
            elsif ( $printing ) {
                print $words[$i];
                $printing--;
                print "\n<br/>\n" if ( $printing == 0 );
            }
        }
    }
}