% perl -e 'print "a" x 5, "\n"'
aaaaa

With that you can easily create a separator string consisting out of 60 spaces.

I always missed this in my shell - until now.

In Zsh have the following expansion:

l:expr::string1::string2:

Pad the resulting words on the left. Each word will be truncated if
required and placed in a field expr characters wide.

See zsh.dotsrc.org. There is also a r: variant which operates in the same way.

And lo and behold:

% echo ${(r:40::-:)A}
----------------------------------------

No more:

A="------------------------------------"

But there a some extra things that must be done before you can call yourself a complete librarian.

1. ID-ing the books you have
2. Storing the information
3. Marking the books
4. Sorting and shelving the books
5. Remembering who borrowed what

ID-ing books

For this I bought a barcode reader that reads the ISBN number of the book's backcover. With book_get (Perl code) I can retrieve the author, title, genre and year published from Google.

% book_get 9789024546497
Cryptonomicon
Neal Stephenson
none
2005
#Cryptonomicon‎by Neal Stephenson, Irene Ketman - 2005

Getting the genre right is a bit of a problem as Google will not always report the correct genre (or just slightly different, i.e. sometimes 'science' and sometimes 'computer science'). I solved this by explicitly asking for the genre in the next step.

Also the html returned is awful, so sometimes this script looses its way.

Storing the information

Getting the information is the first step, now it needs to be stored somewhere. In a SQLite database for instance. I've made a minimal database with only one table which holds all information: title, genre, author, isbn, and a few more items.

With book_sql (perl code) the information retrieved with book_get is normalized (correct the genre) and put into the SQLite db.

Marking the books

To help with this I needed a label writer to print the author, genre and title on a small label. Currently I am not confident enough to automate the printing of the labels so I manually query the database and feed the rows to labelfmt (Perl code). This little scripts uses LaTeX to format the labels and will print the resulting pdf on the labelwriter.

% sqlite3 biblio.db
sqlite> select * from books where title like '%crypto%';
146|9789024546497|Cryptonomicon|Neal Stephenson, Irene Ketman|science fiction|2005|1201339561|

Now I give this text to labelfmt and it will print the label

% ./labelfmt
146|9789024546497|Cryptonomicon|Neal Stephenson, Irene Ketman|science fiction|2005|1201339561|
....

And the labels gets printed:

Next you will needed:

• little pieces of thick paper/carton; this is where you sticker the labels on. Like this:

• little (120 x 120 mm) plastic triangles; which can be glued in each book, so that the book's label can be put inside.

And insert the label:

And another one is ready :-)

Sorting and storing

We decided to catalog our books based on genre. So I made a map to tell which genres are placed where. Sorta like

• COMPUTER - left shelve in the living room
• SCIENCE - middle shelve in the living room
• ... - somewhere else

So there you have it a full blown library setup for you books at home.

Borrowing

Now if somebody want to read one of our book it is simply a matter of: locating the book, getting the label out, writing the person's name on the label and storing the label in a safe place until the book is returned.

This last step could also be automated by using the barcode reader, but the desktop computer in our living room is not powered on 100% of the time. Booting the machine takes too long and makes it too cumbersome if someone just wants to borrow a book.

1. Create a backup with rdup -c
2. Save the output somewhere
3. Upload it to Amazon

Backup:

rdup -c /dev/null dirs/to/backup > rdup-bin-file
s3-upload rdup-bin-file

1. Download the backup file
2. Put it through rdup-snap -c

Restore:

s3-down rdup-bin-file
cat rdup-bin-file | rdup-snap -c -b /tmp/restore

How this works under Ubuntu/Debian with Perl

The Amazon Perl API is already available with Ubuntu. Just

apt-get install libnet-amazon-s3-perl libwww-perl libxml-simple-perl

and you will get all the stuff you need to start developing. Note that perldoc Net::Amazon::S3 is something you really need to read. Also be sure to read the S3 docs from Amazon.

Generic code

S3 works with buckets in which you can place objects (which should be smaller than 5 GB). So before you can do anything you will need to create a bucket.

All Perl files that follow need to have the following code at the start

#!/usr/bin/perl

use strict;
use warnings;
use Net::Amazon::S3;

Next you will need to create a connection with Amazon, this done with your 'access-key-id' and your 'secret-access-key' which I'm not going to tell of course. Code look like this

my $s3 = Net::Amazon::S3->new( 
{   
aws_access_key_id => "my_public_key"
aws_secret_access_key => "my_private_key",
}   
);

Create a bucket

This step needs to be done once. In code:

my $response = $s3->add_bucket( { bucket => "rdup-test1" } ) or 
    die $s3->err . ": " . $s3->errstr;

Upload a file to Amazon

Code:

my $localname = $ARGV[0];
my $bucket = $s3->bucket("rdup-test1");
$bucket->add_key_filename('rdup-backup-200805-23.bin', $localname,
{ content_type => 'application/binary', },
) or die $s3->err . ": " . $s3->errstr;

The arguments for add_key_filename are

1. remote filename
2. local filename
3. hash reference; in this case with the content_type

Download a file from Amazon

Code:

my $localname = $ARGV[0];
my $bucket = $s3->bucket("rdup-test1");
$response = $bucket->get_key_filename('rdup-backup-200805-23.bin',
'GET', $localname) or
    die $s3->err . ": " . $s3->errstr;

The arguments for get_key_filename are:

1. remote filename
2. method, any else than GET allowed?
3. local filename

Webinterfaces

There are also S3 web interfaces out there which will let you point and click to manage your files. I have no experience with any of them, but they seem like a nice idea. You can at least manage your backup files and buckets from your browser; rdup will never have fancy support for this as it has nothing to do with backing up.

Conclusion

You want cheap, off-site backups? With encryption. You can have to now. For rdup-0.6.1 I will add an rdup-s3 tool to automate some of these things. For now you will need to write your own stuff and use the following commands to backup

rdup -c /dev/null ~/mydir | rdup-crypt my-key > rdup-crypted.output
<upload to amazon>
<ready>

And these to restore

<download from amazon>
cat rdup-crypted.output | rdup-crypt -d my-key | rdup-snap -c -b \
/tmp/restore

Ain't that cool?!