my $string = $q->param( 'string' );

unless ( $string ) { error( $q, "Please enter some text." ) };
unless ( $string =~ /^[\w .!?-]+$/ ) {
	error( $q, "Invalid character entered." );
}
local *PIPE;

# This code is more secure, but still dangerous...
# Do NOT use this code on a live web server!!
open PIPE, "/usr/local/bin/figlet '$string' |" or
    die "Cannot open figlet: $!";

print $q->header( "text/plain" );
print while <PIPE>;
close PIPE;