From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <ee9e417a0609251749u4d654339u37548e813f3bae08@mail.gmail.com>
Date: Mon, 25 Sep 2006 20:49:45 -0400
From: "Russ Cox" <rsc@swtch.com>
To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu>
Subject: Re: [9fans] venti backup example vs. 2GB
In-Reply-To: <432bc0dde71c69a75de5f60bf55915ec@tombob.com>
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You can use %.0f to print the number from awk.

Russ


On 9/25/06, Robert Raschke <rrplan9@tombob.com> wrote:
> Hi,
>
> I've been using a backup script modelled on the example in
> /sys/src/cmd/venti/backup.example and the other day it "just" stopped
> working.  On debugging I found that I have now reached the beginning
> of the fifth 500MB arena.  The script uses awk to calculate the
> starting byte offset and that fails with a floating point error (!)
> when we go beyond the 2G mark.
>
> I resorted to a fairly brutal use of bc(1) and that seems to work.
> Here's what I use now (I flipped the 2nd and 3rd parameter to the x fn
> to make printing from bc easier):
>
> #!/bin/rc
>
> rfork e
> . bkup.info
> fn x {
>         echo x $*
>         y=$1
>         if(~ $#$y 0){
>                 $y=0
>         }
>         echo venti/wrarena -h venti_backup_server -o $3 $2 $$y
>         end=`{venti/wrarena -h venti_backup_server -o $3 $2 $$y | grep '^end offset ' | sed 's/^end offset //'}
>         if(~ $#end 1 && ! ~ $$y $end){
>                 $y=$end
>                 echo '#' `{date} >>bkup.info
>                 whatis $y >>bkup.info
>         }
> }
> hget http://127.1:8000/index |
> awk '
> /^index=/ { blockSize=0+substr($3, 11); }
> /^arena=/ { arena=substr($1, 7); }
> /^      arena=/ {
>                 start=substr($5, 2, index($5, ",")-2);
>                 printf("\"x \"; \"%s \"; \"%s \"; s=%s-%s; print s;", arena, $3, start, blockSize);
>         }
> ' |bc -s |rc
>
>
> Robby
>
>