|
Re: [BackupPC-users] Parity (par2) command running on archives even though set to 0
2012-05-31 12:06:54
Pascal Mosimann <pascal.mosimann AT alternatique DOT ch>
wrote on 05/31/2012 11:12:54 AM:
> > Why does BackupPC run the parity command if I've told it
not to by
> passing
> > it a 0? And how do I return to the 3.1 behavior?
According to the
> > documentation, setting it to 0 should disable it, not cause
it to run
> with
> > a parameter of 0... And if for some reason we would
*want* the
> parity to
> > run with a parity of 0, could we have a parameter that
disables it?
> Maybe
> > -1? How do you calculate *negative* parity! :)
>
> Hi Tim,
>
> Same situation here: I don't want to run par2. Because the archive
is
> done on USB drives and it takes too long.
>
> It looks between version 1.16 and 1.17 of BackupPC_archiveHost (see
> http://backuppc.cvs.sourceforge.net/viewvc/backuppc/BackupPC/bin/
> BackupPC_archiveHost?r1=1.16&r2=1.17),
> the condition to run par2 has changed on line 157
> From
> ...
> if ( $parfile != 0 ) {
> ...
>
> to
> ...
> if ( length($parfile) ) {
> ...
>
> I've modified the condition back to "if ( $parfile != 0 )"
and now it
> skips the par2 execution.
Thank you for the followup! I actually changed
it to:
if ( length($parfile) && $parfile !=
0 ) {
(and sent a patch to the list that was seemingly ignored).
My perl-fu is not the greatest; the reason why
I changed it to the above is to be able to handle two conditions: parfile
set to 0, *and* the parfile parameter unset (which is the default, by the
way) or set to an empty string. Perl considers unset variables equal
to an empty string, which also is equal to 0 in a comparison, but I don't
like depending on such assumptions. I'd rather the code be explicit
about what it's trying to accomplish. Maybe that makes me inelegant.
Of course, if you want elegant you could use:
if ( $parfile ) {
because Perl will evaulate an undefined value as an
empty string, and an empty string as a false, and a zero as a false. It's
certainly concise...
But like I said, my perl-fu is not the greatest, and
I prefer explicit to implicit. If this is somehow offensive to the
sense of style of Perl hackers, then so be it.
And let me know: I'd truly like to know the
"right" way to construct an if statement that handles a variable
that is unset, set to a null string or set to zero. Bonus points
for avoiding the warning when using -w... The only way I've been
able to handle this in other projects is something like:
$variable=0 if not defined $variable;
if ( $variable != 0 ) {
Tim Massey
------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
will include endpoint security, mobile security and the latest in malware
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________
BackupPC-users mailing list
BackupPC-users AT lists.sourceforge DOT net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/
|
|
|
