Franz von Sales : PmWiki - Upload Variables

$EnableUpload: The upload.php script is automatically included from stdconfig.php if the $EnableUpload variable is true in config.php. Note that one may still need to set an upload password before users can upload (see UploadsAdmin).
$UploadDir: The directory where uploads are to be stored. Defaults to uploads/ in the pmwiki directory, but can be set to any location on the server. This directory must be writable by the webserver process if uploading is to occur.
$UploadUrlFmt: The url of the directory given by $UploadDir.

The format of the upload link displayed when an attachment is present. No default is set.

$LinkUploadCreateFmt: The format of the upload link displayed when an attachment not present. Defaults to

      <a class='createlinktext' href='\$LinkUpload'>\$LinkText</a>
      <a class='createlink' href='\$LinkUpload'> Δ</a>");

$UploadPrefixFmt: Sets the prefix for uploaded files to allow attachments to be organized other than by groups. Defaults to '/$Group' (uploads are organized per-group), but can be set to other values for sitewide or per-page attachments.

    $UploadPrefixFmt = '/$FullName';    # per-page attachments
    $UploadPrefixFmt = '';              # sitewide attachments

$EnableDirectDownload: When set to 1 (the default), links to attachments bypass PmWiki and come directly from the webserver. Setting $EnableDirectDownload=0; causes requests for attachments to be obtained via ?action=download. This allows PmWiki to protect attachments using a page's read permissions, but also increases the load on the server.
$EnableUploadVersions: When set to 1 (default is 0), uploading a file to a location where a file of the same name already exists causes the old version to be renamed to file.ext,timestamp (instead of being overwritten). timestamp is a Unix-style timestamp.
$UploadNameChars: The set of characters allowed in upload names. Defaults to "-\w. ", which means alphanumerics, hyphens, underscores, dots, and spaces can be used in upload names, and everything else will be stripped.

    $UploadNameChars = "-\w. !=+";    # allow exclamations, equals, and plus