Edit Smart Folder savedSearch manually for command line

I have a set of Smart Folders in High Sierra that index documents on a USB hard drive. The Smart Folders are saved on the USB drive and they work. I have moved the whole content including therefore the Smart Folders on another USB drive and they have stopped working. I have opened one of the savedSearch file and I see that the path is referred many times as absolute. SearchScopes /Volumes/mybackup/documents .... I have tried to edit the file manually from command line with vim, but the old path doesn't change, as it seems that something is restoring the original saved search. The question: is there a way to modify all the searches with a script, without having to delete and recreate them from scratch ?