$ man mail
-s, --subject=SUBJ
send a message with the given SUBJECT
But warn that will be unreadable in Gmail('s Android app etc.), as the
subject will not be properly encoded.
$ echo test|mail -s 'ABC 測試' someu...@gmail.com
What will work needs to look like
$ echo test|mail -s 'ABC =?UTF-8?B?...' someu...@gmail.com
else the user will see 'ABC ???????' in Gmail.
