Ubuntu – How to set fish as the default shell

This is intentional. Most of time the users don't want to accidentally match the hidden files that are invisible for ls (without -a). Usually, files are hidden for a reason, not just to troll you. Also, if * would match hidden files, matching non hidden files would be too tricky.

However, unlike bash shopt -s dotglob is not needed to match hidden files. In bash, shopt -s dotglob is the only way of matching every file in the directory without accidentally matching . or ... However, fish shell can never match . or .. with globs, therefore that's not an issue (if you seriously need to match . or .. for some silly reason, just say them explicitly). Besides, fish tries to avoid having options by design, so it doesn't have dotglob.

To match every single file in the directory, you may want to use bracket expansion to detect files starting with dots, and those which aren't. {.,} is bracket expansion which matches dot that may or may not exist. The star after it matches everything. Because globs in fish cannot match . or .., the following code matches everything except for those two directories (which bash sadly matches, if you use the code below)

cat {.,}*

Just type bash and you'll start the bash shell. type exit to return to fish shell when you're done.