how not to show directory list

Hi

How can I set up apache to disallow the showing of directory listing. For example, when I access a folder that does not have an index.html file, all the files and folders in that directory show up on the browser.

Thank you
Cindy

If you have access to httpd.conf, within all <Directory> blocks, add Options -Indexes in it or just don't put Indexes anywhere, so directory listing is disabled globally.
Conversely, if you have certain directories you want to enable Indexes, just put:
<Directory "/path/to/dir/you/want/to/be/indexes">
Optioins +Indexes # or Indexes
...
</Directory>
For performance wise, it's better not to do it in .htaccess.

Start here -> http://httpd.apache.org/docs/mod/core.html#options

Is it possible to enable directory listings in a specific directory through an htaccess directive when they have been denied at the httpd.conf level?

if main .conf allows that in overriding.

Is there anyway to know whether it is allowed in main.conf
other than trying the option and failing?

I assume if I am allowed to override, the syntax in .htacess
would be:
<Directory full-path-goes-here>
Options Indexes
</Directory>

Since this isn't working, I'm wondering how I can find out why.

<Directory> directive is not allowed in .htaccess. Just put Options +Indexes in your .htaccess and that's it.