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cback-span(1) Kenneth J. Pronovici cback-span(1)


cback-span - Span staged data among multiple discs


cback-span [switches]


This is the Cedar Backup 2 span tool. It is intended for use by people who back up more data than can fit on a single disc. It allows a user to split (span) staged data between more than one disc. It can't be a Cedar Backup extension in the usual sense because it requires user input when switching media.

Generally, one can run the cback-span command with no arguments. This will start it using the default configuration file, the default log file, etc. You only need to use the switches if you need to change the default behavior.

This command takes most of its configuration from the Cedar Backup configuration file, specifically the store section. Then, more information is gathered from the user interactively while the command is running.


The main difference between Cedar Backup version 2 and Cedar Backup version 3 is the targeted Python interpreter. For most users, migration should be straightforward. See the discussion found at cback(1) or reference the Cedar Backup user guide.


Display usage/help listing.
Display version information.
Print verbose output to the screen as well writing to the logfile. When this option is enabled, most information that would normally be written to the logfile will also be written to the screen.
Specify the path to an alternate configuration file. The default configuration file is /etc/cback.conf.
Specify the path to an alternate logfile. The default logfile file is /var/log/cback.log.
Specify the ownership of the logfile, in the form user:group. The default ownership is root:adm, to match the Debian standard for most logfiles. This value will only be used when creating a new logfile. If the logfile already exists when the cback script is executed, it will retain its existing ownership and mode. Only user and group names may be used, not numeric uid and gid values.
Specify the permissions for the logfile, using the numeric mode as in chmod(1). The default mode is 640 (-rw-r-----). This value will only be used when creating a new logfile. If the logfile already exists when the cback script is executed, it will retain its existing ownership and mode.
Record some sub-command output to the logfile. When this option is enabled, all output from system commands will be logged. This might be useful for debugging or just for reference.
Write debugging information to the logfile. This option produces a high volume of output, and would generally only be needed when debugging a problem. This option implies the --output option, as well.
Dump a Python stack trace instead of swallowing exceptions. This forces Cedar Backup to dump the entire Python stack trace associated with an error, rather than just progating last message it received back up to the user interface. Under some circumstances, this is useful information to include along with a bug report.
Display runtime diagnostic information and then exit. This diagnostic information is often useful when filing a bug report.


This command returns 0 (zero) upon normal completion, and six other error codes related to particular errors.

The Python interpreter version is < 2.7.
Error processing command-line arguments.
Error configuring logging.
Error parsing indicated configuration file.
Backup was interrupted with a CTRL-C or similar.
Other error during processing.


Cedar Backup itself is designed to run as root, since otherwise it's difficult to back up system directories or write the CD or DVD device. However, cback-span can be run safely as any user that has read access to the Cedar Backup staging directories and write access to the CD or DVD device.




/etc/cback.conf - Default configuration file
/var/log/cback.log - Default log file



If you find a bug, please report it.

If possible, give me the output from --diagnostics, all of the error messages that the script printed into its log, and also any stack-traces (exceptions) that Python printed. It would be even better if you could tell me how to reproduce the problem, for instance by sending me your configuration file.

Report bugs to <> or by using the BitBucket issue tracker.


Written and maintained by Kenneth J. Pronovici <> with contributions from others.


Copyright (c) 2004-2011,2013-2015 Kenneth J. Pronovici.

This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

July 2015 Cedar Backup 2