Proper CLI usage in Gitlab

When trying to run
sudo -u mattermost ./mattermost -config=/var/opt/gitlab/mattermost/config.json -version
I get: command mattermost can't be found.

Trying this however:
sudo -u mattermost /opt/gitlab/embedded/bin/mattermost -config=/var/opt/gitlab/mattermost/config.json -version
is returning following error:

panic: Failed to load system translations for 'en'

goroutine 1 [running]:
github.com/mattermost/platform/utils.GetTranslationsBySystemLocale(0xc820162460)
	/go/src/github.com/mattermost/platform/utils/i18n.go:44 +0x19a
github.com/mattermost/platform/utils.InitTranslations()
	/go/src/github.com/mattermost/platform/utils/i18n.go:29 +0x2e9
main.main()
	/go/src/github.com/mattermost/platform/mattermost.go:54 +0x2c

goroutine 17 [syscall, locked to thread]:
runtime.goexit()
	/usr/local/go/src/runtime/asm_amd64.s:1721 +0x1

goroutine 5 [syscall]:
os/signal.loop()
	/usr/local/go/src/os/signal/signal_unix.go:22 +0x18
created by os/signal.init.1
	/usr/local/go/src/os/signal/signal_unix.go:28 +0x37

goroutine 6 [chan receive]:
github.com/alecthomas/log4go.(*ConsoleLogWriter).run(0xc82000e580, 0x7fe2513041e8, 0xc820032010)
	/go/src/github.com/mattermost/platform/Godeps/_workspace/src/github.com/alecthomas/log4go/termlog.go:33 +0x69
created by github.com/alecthomas/log4go.NewConsoleLogWriter

Any ideas?
Thanks!