tar not reading if output directed to /dev/null Post: 302351501

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Operating Systems Linux Ubuntu tar not reading if output directed to /dev/null Post 302351501 by bakunin on Tuesday 8th of September 2009 06:57:21 PM

09-08-2009

Registered User

First off, I'd like to state that i do NOT have a problem. I just want to achieve a better understanding. So you don't need to tell me workarounds, as i have already found one.

Quote:

Originally Posted by thegeek

Before that why you would want to tar and check the integrity, better you can do by reading all the files !!

This is exactly what i was expecting tar to do: read all the files.

Quote:

Originally Posted by methyl

The parameter after "-f" is the archive filename. A value of "-" when there is no pipeline has no sensible meaning

Sorry, but this is simply not true: the dash as a filename is signifying <stdout> and if i use a redirection or a pipeline to manipulate tars output further should make no difference.

In fact (as i have stated in my first post) the command worked the way i wrote it when i used a real file (instead of /dev/null) as output destination. It is this inconsistency - the command reading all the files when a real file is the destination and not working, when the destination is /dev/null - i want to understand.

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LEARN ABOUT DEBIAN

barrybackup

BARRYBACKUP(1)						      General Commands Manual						    BARRYBACKUP(1)

NAME

       barrybackup - Barry Project's backup program for the BlackBerry handheld

SYNOPSIS

       barrybackup [-?][-d]

DESCRIPTION

       barrybackup is a GUI application for backing up and restoring Blackberry handheld databases.

       The  application  allows for filtering of databases for both backup and restore, so not all databases need to be backed up at once, nor all
       restored.

       Backups and configuration files are stored by default in the user's home directory, under ~/.barry/backup/PIN.	This  destination  can	be
       changed in the config dialogs, per device.

       The backup files are compressed tarballs containing specially named files for each record of the databases.

OPTIONS

       -d     --debug-output Enables low level protocol debug output written to stdout/stderr.

       --display=DISPLAY
	      Specify which X display to use.

       -?     --help Show summary of options.

       -h, --help
	      Show summary of options.

TAR FORMAT

       Backups are stored in tar format, compressed with gzip.	Backup files are named with the following pattern:

	    PIN-YYYYMMDD-HHMMSS[-tag_name].tar.gz

       The tag name is optional and is used to name a particular backup.

       Each record is appended to the tar file using the following pattern for the filename:

	    DBname/RecordID RecordTypeID

       That is, the database name is used as the directory name, and the filename contains the record ID and record type ID separated by a space.

       Database names can contain spaces.

       Record  IDs  are generally unique, but not all Blackberry devices mandate this, so it is possible, but rare, to have two records in the tar
       file with the same filename.  This is ok.  The only problem you'd see is if you expanded such a tar file  to  a	filesystem.   The  restore
       process just reads in the filename sequentially and writes them to the device, so duplicate record IDs are not a problem.

AUTHOR

       barrybackup is part of the Barry project.  This manual page was written by Chris Frey.

SEE ALSO

       http://www.netdirect.ca/software/packages/barry

								   July 28, 2009						    BARRYBACKUP(1)

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