Works fine for me:
$ /opt/couchbase/bin/cbreset_password --help
Usage: cbreset_password [options]
Options:
-h, --help show this help message and exit
-r ROOT root directory - defaults to /opt/couchbase/bin/..
4.1.0-dp, Ubuntu 14.04:
$ cat /opt/couchbase/VERSION.txt
4.1.0-4908
$ cat /etc/issue
Ubuntu 14.04.3 LTS \n \l