If $gbl_SearchString = "le"
Then your expression will find records that contain words such as:
$gbl_SearchString & "*" , with $gbl_SearchString = "ap" on the other hand will find
You can also use "*" & $gbl_SearchString & "*"
to find text that contains the contents of the global variable at any point in the word.
Thanks I was wondering if the quotes had to be there?
Yes. (For quicker answers on a question like that, you can always try it and see what happens.)