--help should not panic & other argument-passing interrogations

[drzraf]

$ go version
go version go1.13.8 linux/amd64

$ cd ./go/bin/ && ./SystemdJournal2Gelf --help 
panic: usage: SystemdJournal2Gelf SERVER:12201 [JOURNALCTL PARAMETERS]

goroutine 1 [running]:
main.main()
	~/go/src/github.com/parse-nl/SystemdJournal2Gelf/SystemdJournal2Gelf.go:164 +0x64d


$ ./SystemdJournal2Gelf localhost:12201 -- --version
Failed to add match '--version': Invalid argument
# ^^ I would expect it to be passed to journald...


$ ./SystemdJournal2Gelf localhost:12201 --version
panic: could not parse journal output: invalid character 's' looking for beginning of value
# ^^ Why?

[SjonHortensius]

I see your point but all of these issues can be explained:

• --help panics because I used panic instead of fmt.Printf + os.Exit (I can fix this and you'd get the same error without the backtrace) I understand this might seem as if something went wrong

• -- --version comes from journalctl: see journalctl -- --version. I see your point here as well as -- would normally be used as the option vs filter separator, but it currently isn't in this script

• --version fails because this script expects JSON output. --version outputs non-json data which it cannot parse