Using the -I option, BRU can be set to run interactively with a program such as brutalk (see Appendix I, “The brutalk Program”). If there is no terminal present, you can direct BRU to write its queries to a fifo (first-in-first-out buffer file) and read responses from a different fifo. The interactive program, in turn, watches the output from BRU and directs its activities accordingly, responding through BRU’s input response fifo, just as though the responses were made from an interactive terminal.
When BRU was first installed on your system. The installation created the two fifos listed below. The commands listed below, can be used to create the fifos if for some reason they where not created during install, or you need to create additional fifos.
$ mknod /bru/bru.q p
$ mknod /bru/bru.r p
To create different fifos i.e. for running multiple BRU jobs.
$ mknod /bru/myfifo.q p
$ mknod /bru/myfifo.r p
In order to use the brutalk feature you will need to add the option listed below to your bru command line.
-Ib
If you created a different set of fifos, (i.e.: if you are running multiple BRU jobs) then you would add the following argument to your BRU command
-Iq,/bru/myfifo.q -Ir,/bru/myfifo.r
to the desired BRU command line which ultimately gets executed. The first time BRU needs to communicate with an operator, it will open the two fifos, write a query to the bru.q fifo, and wait for a response from the bru.r fifo. The brutalk program, which is a simple program provided with BRU, can be used to read the query and send a reply. Here is the command to start brutalk if you are running the standard fifos as explained in the previous example:
brutalk
If however you are writing to a different set of fifos simply run the example below
brutalk [-t ttyname] /bru/bru.r
or
brutalk [-t ttyname] /bru/bru.q /bru/bru.r
The second form is used if you want brutalk to timeout after a few seconds if there are no queries ready to be read. The brutalk program will continue to read queries and send replies until either BRU exits, or a CTRL-D (EOF) is typed at the terminal. The optional ttyname parameter can be used to force brutalk to interact with the user via some terminal steam other than /dev/tty. See section 5: “Archiving Files: The BRU Backup Function,” “Running without User Intervention: -B.” If the -B option is used, BRU is forced to run in the background and will terminate if a problem occurs.
The selection of either method depends on what the desired recovery is when interaction is necessary. If you prefer to have the backup terminate and not rerun, then use the -B option. However, if you want to be able to recover from an unexpected situation (for example, if the tape is simply off line), and to rerun or continue the backup, then use the -I option, and use brutalk to resolve the problem when it is convenient. brutalk can also be used by someone dialing into the system to check on BRU’s progress, since it can be run by anyone from any terminal. NOTE: Only the permissions on the read/write fifos enforce security.