instead of allowing xargs to execute the action with no positional
parameters.
Also don't try to write to .latest_version if there's no write
permission. This is supposed to be a background/optional operation, so
we don't want to show an error message in this case.
And use Zsh globs instead of find with -exec, and find won't fail if
there's an error with the -exec command.
before initial check for latest version. Not all versions of Zsh or all
OSs are affected. Error seen with Zsh 5.6.2 running on FreeBSD is:
_zimfw_version_check:10: no such file or directory: /path/to/.latest_version
Last-minute minor fixes:
* Delete .latest_version after upgrading. Having a cache brings in these
complexities.
* Print warning to stderr, to distinguish it from the normal output.
* Update help to be in sync with the README.md.
Eric Nielsen