Sets the SMB username or username and password.
If %password is not specified, the user will be prompted. The client will first check the USER
environment variable, then the LOGNAME variable and if either exists, the string is uppercased. If
these environmental variables are not found, the username GUEST is used.
A third option is to use a credentials file which contains the plaintext of the username and
password. This option is mainly provided for scripts where the admin does not wish to pass the
credentials on the command line or via environment variables. If this method is used, make certain
that the permissions on the file restrict access from unwanted users. See the -A for more details.
Be cautious about including passwords in scripts. Also, on many systems the command line of a running
process may be seen via the ps command. To be safe always allow rpcclient to prompt for a password
and type it in directly.