Re: script to see if dar incremental backup recorded any changes

If I capture the output from dar incremental backup creation, is it
accurate to determine whether the backup recorded any changes by
examining the two lines:
N inode(s) saved
N inode(s) recorded as deleted from reference backup

if either N>0, then the incremental backup recorded some changes,
correct?  Does this cover all cases, including deltas?

This would be the fastest technique, obviously.

On Thu, 6 May 2021 21:59:01 +0200
Denis Corbin <[email protected]> wrote:

> On 06/05/2021 00:56, imschmeg wrote:
> > What is the most robust and fastest way to check if a dar
> > incremental backup recorded any changes?  
> 
> unless you find a bug, there is not a less robust way than an other to
> perform a given action.
> 
> For the fastest way, yes, I cannot find any faster:
> 
> > 
> > I could do:
> > dar -l backup -q
> > 
> > and parse the output with awk to see if any of the lines "fully
> > saved", "binary delta patch" or "inode metadata only" contain non-0
> > counts. And then also check the "N file(s) have been recorded as
> > destroyed..." line.
> > 
> > This however seems a bit fragile, as it depends on the format of the
> > summary staying the same.  Is there a better way?
> >   
> 
> I agree, this is fragile, it also depends on the locale (messages can
> be translated, depending on the value assigned to the LANG environment
> variable: for example check this: "export LANG=fr_FR.utf8 ; dar -V"
> 
> If you don't want to parse the text output of a command outputting
> text, but rather want structured information about the backup
> (integer values, counters, and so on, in different fields), the best
> way is to directly rely on the libdar API:
> 
> Today, you can make a simple program in C/C++ or in Python3.
> 
> For your use case, (obtaining just the number of saved files in an
> existing backup) this is not much complicated to do
> 
> > 
> >   
>