Ciao a tutti, è venerdì! Se avete due minuti di tempo, volevo indicarvi un articolo su un algoritmo non banale, molto ben descritto qui:

http://research.swtch.com/sparse

This is the story of a clever trick that’s been around for at least 35 years, in which array values can be left uninitialized and then read during normal operations, yet the code behaves correctly no matter what garbage is sitting in the array.

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Userful Commands:

1. keep-lines
2. sort-lines

For more similar options, see this "working with lines"

For playing with rectangles of text, see this tip

I stumbled upon a very brain-f**k error on Oracle 10g on these days.

Context: the following query [sql]SELECT * FROM (
SELECT TO_NUMBER(CUSTOMER_ID) AS SNDG FROM BAD_CODES_TABLE WHERE
AND I_LIKE=UPPER(‘STATIC_CONDITION’) AND CUSTOMER_ID NOT LIKE ‘%P%’ ) S WHERE TO_NUMBER(S.SNDG) >2000[/sql] could trigger a Invalid number if CUSTOMER_ID column contains invalid numbers.

Why?

Well…if you ask to “explain plan”, you will get something like

• a table full scan
  • Filter Predicates AND
    • I_LIKE=UPPER('STATIC_CONDITION')
    • TO_NUMBER(S.SNDG) >2000
    • CUSTOMER_ID NOT LIKE '%P%'

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How I Structure My Flask Applications Flask has been my preferred web framework as of late. I think it has a great core feature set and Armin, the main author, has done well to keep its API minimal and easy to digest even for developers that are relatively new to Python. However, given that it is a rather minimal framework, it can be often difficult to decide on how to structure an application after it reaches a certain level of complexity. It tends to be a common question that comes up in the #pocoo IRC channel.In this article I intend to share how I structure Flask applications. To help support this article Ive written a very basic application that Ive arbitrarily named Overholt. If you plan on following along I recommend having the source code open in your browser or a code editor.

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ZFS is a very innovative file system….

ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include protection against data corruption, support for high storage capacities, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs. ZFS is implemented as open-source software, licensed under the Common Development and Distribution License (CDDL). The ZFS name was a trademark of Oracle^[3] until September 20, 2011.^[4]

[…]

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So you know I need Emacs on every PC I use.

On windows7 I stick with a linuxVM when possibile, but sometime you need maximum speed, and EmacsWin32 is a good guy. Then I read the exact description of my problem…

Emacs on my Windows 7 work laptop was annoying slow when starting (around 10s). If closed and restarted, startup was immediate until, after about 30 seconds, it was slow again. According to Google, slowness might be due to failing DNS lookups of the laptop's hostname.

and I find out this solution: stop netlogon service via a command like

net stop netlogon

The add also this line to your .emacs...

(setq w32-get-true-file-attributes nil)

Code Me Mabye

Hey, I just met you, and this is crazy  But here's my number, so call me maybe And all the other boys, try to chase me,  But here's my number, so call me maybe

Code Zauker 0.0.9 is OUT

This release spot a optimized index (case sensitive search was stripped down to gain more space), and compatibility with er_zauker indexer (so you can span millions of server using Erlang ;)

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!UPDATED!

Okey I love emacs, you are allowed to say I am a nerd. But I use emacs. So I could solve your problems with a Ctrl-Alt-x kung fu combination, involving yoga-like finger movements.

So do not mess with me… :D (I am like the Zohan, only with glasses :)

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E’ facile fare un backup con sql server: Basta selezionare tasto destro Tasks>>Backup su un db. Ma come fare il restore?… Ecco un semplice script che chiarisce la cosa (non sempre lampante dallo wizard di restore….): [sql] – Usare il seguente comando per recuperare i parametri sorgente da usare nella MOVE – Nel nostro caso ssaranno MY_BACKUP e MY_BACKUP_log RESTORE FILELISTONLY FROM DISK = N’C:\TEMP\MY_BACKUP\Backup.bak’ ;

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cvs2svn/cvs2git is a tool that can be used to migrate CVS repositories to newer version control tools, including git. git is a distributed version control system most famous for being used for Linux kernel development. The program used to convert to git, called cvs2git, is distributed as part of the cvs2svn project.

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Git Flow is a very popular workflow for working with git. I have the lucky to set up Git on a medium sized project, and the following article helped me a lot… I report you the schema too, because it was very useful in a presentation I attended.

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In the last seven months I learned git, working for a dozen of projects. On some of them I was the master&commander, on others I only set up the streams and let the young Jedi find the way to the delivery. Via trial and error I find out a bunch of userful commands.

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ForceBindIP is a freeware Windows application that will inject itself into another application and alter how certain Windows Sockets calls are made, allowing you to force the other application to use a specific network interface / IP address. This is useful if you are in an environment with multiple interfaces and your application has no such option for binding to a specific interface.

via ForceBindIP - Bind any Windows application to a specific interface.

Using iPhone/Android Tethering features, you can end up with a

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In a nutshell, xargs is an alternative to fully expanded shell for loops. Given the right options, xargs can be made to exhibit for-loop-like behavior. But out of the box, it is a way to pipe a bunch of arguments to a single command in one fell swoop.

This can save a great deal of compute time if you are piping a long list of arguments to a command rather than iterating over them one at a time.

In  A small primer on xargs you will find a deep explanation on xargs usage. The article teach me a bunch of tricks I am not aware of (and I know Unix from ‘93….yes, 1993…).

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Replacing on entiere set of files is hard in Emacs. But I find the correct mumbo-magic procedure, and gifted it to you:

• Call dired to list files in dir, or call find-dired if you need all sub directories.
• Mark the files you want. You can mark by regex by typing 【%m】.
• Type Q to call dired-do-query-replace-regexp.
• Type your find regex and replace string. (➲ common elisp regex pattern)
• For each occurrence, type y to replace, n to skip. Type 【Ctrl+g】 to abort the whole operation.
• Type ! to replace all occurrences in current file without asking, N to skip all possible replacement for rest of the current file. (N is emacs 23 only)
• To do the replacement on all files without further asking, type Y. (Emacs 23 only)
• Call ibuffer to list all opened files.
• Type 【*u】 to mark all unsaved files, type S to save all marked files, type D to close them all.

See this great article for more information