d44b6ae6cb
https://github.com/koalaman/shellcheck/wiki/SC2086 Double quote to prevent globbing and word splitting. https://github.com/koalaman/shellcheck/wiki/SC2166 Prefer `[ p ] && [ q ]` as `[ p -a q ]` is not well defined. https://github.com/koalaman/shellcheck/wiki/SC2219 Instead of `let expr`, prefer `(( expr ))` . Signed-off-by: Anders Kaseorg <andersk@mit.edu>