Add a non-busy path to safe_sleep for modern versions of bash #3870
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The current implementation of
safe_sleep.shis a busy wait.This seems to exist because
sleepis not a shell builtin, and it can't be assumed all environments have the sleep binary.Bash 4 and above support the builtin
readcommand, which can be used as a sleep with the timeout feature. This pattern is described here:https://github.com/dylanaraps/pure-bash-bible?tab=readme-ov-file#use-read-as-an-alternative-to-the-sleep-command
Despite Bash 4 shipping 16 years ago, bash 3.x is still the default shipped on MacOS due to 4+ being licensed as GPL3, so the busy wait was retained as a fallback.
Also the condition in the busy wait was switched from
!=to-lt, which is a safer comparison and avoids possibility of an infinite loop.Fixes #2380
#3143 has another similar approach, which relies on conditionally checking for sleep or ping binaries to provide a sleep functionality.