Bash's list of behaviours that aren't POSIX-compliant is longer than I expected: https://www.gnu.org/software/bash/manual/html_node/Bash-POSIX-Mode.html
I used fish for a while and liked it, but POSIX-ish shells work with everything. These days I use a heavily customised zsh.
miniblog.
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Many excellent Hubot packages haven't been touched in five years. Is there a newer alternative?
My experience is that group chats, especially in a work context, are hugely enriched with customised bots.