os.environ does not have LANGUAGE in Centos8.

[jexShain]

There is no LANGUAGE available on environ of centos, so there is no way to select a new LANGUAGE, even though only English is available.

[mattrose]

According to my reading, LANGUAGE and LANG are two slightly different variables with slightly different purposes and LANGUAGE is present on other linuxes. I'd much rather use LANG as a fallback if LANGUAGE doesn't exist, rather than replacing LANGUAGE with LANG entirely

[jexShain]

What you said is very reasonable, so I will add Lang as a judgment. Is it appropriate?If you think so, I will continue to revise it.

[mattrose]

This is ... closer, but LANG should only ever return one element. LANGUAGE returns a colon separated list, but LANG only ever returns one language. You should be able to just use the string that split returns. so something like:

 elif 'LANG' in os.environ:
        target = os.environ['LANG'].split('.')[0]

[mattrose]

just another Q: What does locale output in centos 8?

[jexShain]

Thank you for your advice. I have revised the language selection again to facilitate the expansion of the website language in the future. Running in my environment on CentOS 8 is zh_ CN is en after changing the English is en_US.Also on Debian, language is zh_ CN.

[mattrose]

Looks good, thank you!