Oct 202013
 

As system administrator, or simple user that uses Linux on its desktop sometime you notice that something it’s eating all the memory of your system.
As first thing be sure to understand how Linux manage memory, I’ve be called too many time by scared users that did a free and were unable to read its output properly, in short, don’t worry if the Linux Kernel it’s using your memory to cache file.

< rant on >

To my “beloved” users:

Be assured that the Kernel developers can do a better job than you (and me) in find a good algorithm to cache file and free that memory area when a process need it, so please don’t ask me to put in cron some job that run something like that :

echo 3 > /proc/sys/vm/drop_caches

After that you’ll have more free memory available on the system, true, but the system will have to re-read all the files from the disk, so in terms of performance this is usually a bad move.

< /rant >

But now let’s take a look at a nice small program that can help us in find which process/users are using, for real, the memory of our systems.

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Oct 122013
 

Sometimes a program or software don’t start for a syntax error, and if you check the files there is nothing wrong..apparently.
There are a lot of characters that usually are not printed if you use a normal text editor, but you can easily check if they are present with your terminal and the command cat.

As first thing let’s create a simple text file with these special characters, open a terminal and run the command:

printf 'testing\012\011\011testing\014\010\012more testing\012\011\000\013\000even more testing\012\011\011\011\012' > /tmp/testing.txt

Now if you open the file with an editor you’ll have different results.
A simple cat will show:

$ cat /tmp/testing.txt 
testing
		testing
 
more testing
 
        even more testing

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Oct 042013
 

syncHave you finish your cloud space on Dropbox, Google Drive or one of the many cloud storage providers ? Or maybe you don’t trust them and you’d prefer a solution made with your computer/vps/Server ?

Good news, from some time there is a new solution available: BitTorrent Sync

BitTorrent Sync by BitTorrent, Inc is a proprietary peer-to-peer file synchronization tool available for Windows, Mac, Linux, Android, iOS and BSD. It can sync files between devices on a local network, or between remote devices over the Internet via secure, distributed P2P technology, so in short you can setup your own cloud storage and share your files among your devices.

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Oct 012013
 

steam_os

Some days ago Valve announced it’s new, and not so secret, project SteamOS :

“Thousands of games, millions of users. Everything you love about Steam.
Available soon as a free operating system designed for the TV and the living room.”

In short, soon there will be a new Linux distribution tailored to get the max from Steam and its games,

“SteamOS will be available soon as a free download for users and as a freely licensable operating system for manufacturers. Stay tuned in the coming days for more information”

about manufacturer Valve claims that it’s in contact with different hardware vendors to make “a variety of Steam gaming machines.” All will be running SteamOS and are expected to start hitting retail in 2014.
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Sep 192013
 

Fool those who try to portscan your system!
The Portspoof program is designed to enhance OS security through emulation of legitimate service signatures on otherwise closed ports. It is meant to be a lightweight, fast, portable and secure addition to the any firewall system or security infrastructure.

The general goal of the program is to make the port scanning software (Nmap/Unicornscan/etc) process slow and output very difficult to interpret, thus making the attack reconnaissance phase a challenging and bothersome task

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