If you do not specify a device on the command line, BRU defaults to the first entry in the /etc/brutab file. See Chapter 13, “Setting Device Parameters: The brutab File.”
The example below shows how to specify the device on the command line. It creates an archive from the files in the /usr/src directory, using a 20 gigabyte tape inserted into the drive mounted as ntape0. It is important to know that the file that follows the -f need not be a device file, although this is the usual case. You may also use files on the system as archiving device files. However, you will experience an error if you set the BRUTABONLY=YES global brutab parameter in the brutab file.
bru -c -f ntape0 -s 20GT
See “Specifying Media Size: -s,” below.