Sep 21

[Bash,Linux] Very fast disk shredding/data erasure script

Bash, Linux , , , Add Comment (0)

Before I have setted up my encrypted partitions I had to fill them with random sequention of data.
I’ve noticed that dd if=/dev/urandom of=DEVICE is very slow. It has 3-4 MB/second on my computer.
I wanted to make it faster. Here is my solution:
1. Create in tmpfs located in RAM memory large file (about 100 MB) made of pseudo-random sequence (/dev/urandom).
2. Write this file from memory sequentially to the disk.
Speed of this approach is even 34 MB/s – 10 times faster!!.
Unfortunately, this aproach might not be as secure as dd if=/dev/urandom of=DEVICE
Before you do anything backup your data and be sure what are you doing!!!
My implementation: Read More


Jul 24

[Ubuntu] Nice Amarok-like music Player

Linux, Ubuntu , , Add Comment (0)

I’ve used Amarok for a long time. Unfortunately, interface of Amarok 2 has  been remarkably changed.  I like “old” Amarok’s interface so I’ve found Exaile – Amarok like music player for Gnome written in Python. Read More


Apr 18

[Linux] How to execute SQL query on Firefox history

Linux, SQL, Ubuntu , , , Add Comment (0)

1. If you don’t know anything about SQLite, please read:

http://en.wikipedia.org/wiki/SQLite

2. Install sqlitebrowser:

sudo apt-get install sqlitebrowser

3. Run sqlitebrowser
4. Open file:
/home/your username/.mozilla/firefox/your profile/places.sqlite
It’s a SQLite database where firefox stores information about history.
5. Execute following command:

SELECT url FROM moz_places WHERE url LIKE "%wojtekrj.net%"

6. You should have list of all vistied by you pages from my blog.


Apr 18

[Linux] How to check if program has memory leaks

C++, Linux , Add Comment (1)

You can check your program using command:

valgrind your_program

Example of usage:
We have following C++ program (tst.cpp):

int main() {
	int * tab = new int[1000000];
	return 0;
}

Obviously it generates memory leak. We compile it to tst file and execute:

valgrind tst

Read More