Retry commands on the command line without all the loops you always used!
# Stop retrying after 10 tries
retry --max 10 -- curl -I https://unstable.site
# Stop retrying after 10 tries and wait 5 seconds between the each try
retry --max 10 --interval 5 -- curl -I https://unstable.site
# Stop retrying if exit code is 1
retry --exitcode 1 -- curl -I https://unstable.site
# Suppress stdout and stderr from the command
retry --quiet -- curl -I https://unstable.sitecargo install retry-cmd