Certainly I would not say “don’t ever quote strings in Bash”, that’s plainly wrong. Actual advice I would give is to use Shellcheck for all shell scripting as it will generally correctly warn about missing quoting (e.g. of shell vars) and does warn about tilde not being expanded in quotes.
It does not warn about `echo "$PATH":~`, though, but that is perhaps an uncommon “error” that is more about your contrived test case (not that Calvinball is good, ofc).
It does not warn about `echo "$PATH":~`, though, but that is perhaps an uncommon “error” that is more about your contrived test case (not that Calvinball is good, ofc).