bb0fd9838396d159aeac3e7515923cf0918e4e19
max
  Tue Jul 2 08:29:23 2019 -0700
adding linebreak suggested by chmalee, refs #23703

diff --git src/hg/lib/customTrack.c src/hg/lib/customTrack.c
index 89937dd..d11b0be 100644
--- src/hg/lib/customTrack.c
+++ src/hg/lib/customTrack.c
@@ -765,31 +765,31 @@
         if (customTrackIsCompressed(fileName))
             {
             customText = prepCompressedFile(cart, fileName,
                                 CT_CUSTOM_FILE_BIN_VAR, CT_CUSTOM_FILE_VAR);
             }
 	else if (customTrackIsBigData(fileName))
 	    {
 	    // User is trying to directly upload a bigData file; pass data to
 	    // customFactory, which will alert the user that they need bigDataUrl etc.
 	    customText = prepBigData(cart, fileName, CT_CUSTOM_FILE_BIN_VAR, CT_CUSTOM_FILE_VAR);
 	    }
         else
             {
             /* unreadable file */
             struct dyString *ds = dyStringNew(0);
-            dyStringPrintf(ds, "Unrecognized binary data format in file %s", fileName);
+            dyStringPrintf(ds, "Unrecognized binary data format in file %s. You can only upload text files on this page. If you have a binary file, like bigBed, bigWig, BAM, etc, copy them to a webserver and paste the URL of the file into the text box here or create a track hub for them. For more details, our <a href='https://genome.ucsc.edu/goldenpath/help/hgTrackHubHelp.html#Hosting'>documentation</a> discusses where you can host binary files.", fileName);
             err = dyStringCannibalize(&ds);
             }
 	}
     }
 customText = skipLeadingSpaces(customText);
 
 /* get track description from cart */
 char *html = NULL;
 char *docFileName = cartOptionalString(cart, CT_CUSTOM_DOC_FILE_NAME_VAR);
 char *docFileContents = cartOptionalString(cart, CT_CUSTOM_DOC_FILE_VAR);
 if (isNotEmpty(docFileContents))
     html = docFileContents;
 else if (isNotEmpty(docFileName))
     {
     if (customTrackIsCompressed(docFileName))