From within the CL interface directly there is not a way I know of.
When I need to go batch crazy with my campaigns, I export them as a JSON, edit the heck out of the JSON, and re-import.
WARNING: I DON"T RECOMMEND THIS FOR SANE CL USERS
As a UNIX/Linux user with python ... I can go pretty crazy pretty fast and easily:
sed -i -e 's/tagSymbol: "-"/tagSymbol: "@"/g' export.json
Then drop/delete the old campaign and import the new export all mangled up.