Shell script with ifconfig commands

This is one of the most inefficient ways to get many IP addresses applied to one network interface. Anyways it allows to create as many aliases for the interface as you like so you should create shell script and execute it every time Linux boots.

touch /path/to/script.sh
chmod +x /path/to/script.sh
vi /path/to/script.sh

Now you should add there shell lines which will apply IP addresses, e.g. the following one applies 60 IP addresses to eth0 interface:

for n in {3..63};  do ifconfig eth0:${n} 10.10.10.${n} netmask 255.255.255.0 up; done

If you type ‘ifconfig’ now you will very long output like this one:

eth0:3  Link encap:Ethernet  HWaddr 00:50:8D:D1:24:DB
          inet addr:10.10.10.3  Bcast:10.10.10.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:10 Base address:0x2000 

eth0:4  Link encap:Ethernet  HWaddr 00:50:8D:D1:24:DB
          inet addr:10.10.10.4  Bcast:10.10.10.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:10 Base address:0x2000

...

eth0:63  Link encap:Ethernet  HWaddr 00:50:8D:D1:24:DB
          inet addr:10.10.10.63  Bcast:10.10.10.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:10 Base address:0x2000

If you decide to delete those IPs you can run the following line as a remedy:

for n in {3..63};  do ifconfig eth0:${n} 0.0.0.0 &> /dev/null; done

Once you finished editing /path/to/script.sh script you should add it to startup, so put the line /path/to/script.sh into /etc/rc.local file that Linux executes every time it boots. Please notice that in various distributions this file may be missing so consult with distro’s docs to get where it is stored.

Redhat/Centos/Fedora network scripts

Users of these Linux distributions can apply ranges of IP addresses using ifcfg-eth0-range0 files which are read during initialization of network interfaces during boot up process. The following example will make Linux to apply 200 IP addresses to eth1 during booting:

[root ~]#cat /etc/sysconfig/network-scripts/ifcfg-eth1-range0

IPADDR_START=192.168.1.1
IPADDR_END=192.168.1.200
CLONENUM_START=10

CLONENUM_START value specifies starting identifier of alias that will be applied to eth1 interface, in above example the first 192.168.1.1 will be assigned to eth1:10 alias. The last IP of the range 192.168.1.200 will be applied to eth:210 sub-interface. This is totally easy approach.

Loopback interface

Did you know that by one line presented below you assign 1022 virtual IP addresses to your Linux system? Here it is:

ifconfig lo:0 10.0.0.1/22

Now you can make sure of this by pinging IPs from that range (10.0.0.1 – 10.0.3.254).

[root ~]#ping 10.0.0.1 -c 1
PING 10.0.0.1 (10.0.0.1) 56(84) bytes of data.
64 bytes from 10.0.0.1: icmp_seq=1 ttl=64 time=0.063 ms

--- 10.0.0.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.063/0.063/0.063/0.000 ms

...

[root ~]#[root@whitehorse /]# ping 10.0.3.254 -c 1
PING 10.0.0.1 (10.0.3.254) 56(84) bytes of data.
64 bytes from 10.0.3.254: icmp_seq=1 ttl=64 time=0.063 ms

--- 10.0.3.254 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.063/0.063/0.063/0.000 ms

If you still feel that the first suggested way meets your requirements better than the third one please read more about loopback interface at wikipedia — loopbacks are much more useful than aliases in most cases.

Hope it helps!

sudo aptitude install pdftk
(if you run Fedora, RedHat or CentOS use this one: sudo yum install pdftk)

Split large pdf into many one-page files:

pdftk largepdfile.pdf burst

(as the result you will get many small files like pg_0001.pdf, pg_0002.pdf and so on).

Merge files into one PDF file:

pdftk *.pdf cat output onelargepdfile.pdf

pdftk is extremely powerful and makes it possible to do almost anything with input pdf files. Thus above two commands are just examples showing how to split and merge pdf files in Ubuntu easily.

Today it came to my mind that it is time to make sensitive information stored on my usb flash drive encrypted but still transportable and easy to use. But I don’t want to have whole my 32 GB usb drive fully encrypted using truecrypt or something similar. It is just toooo slow. I also don’t want to use GPG for uncompressing files and directories every time I would like to read them and then create new GPG compressed file every time I save changes. This eats too much of my time and system resources. At the same time it is necessary to be able to use that usb drive under windows, mac, linux whatever (read/write files) but still have my directory structure with sensitive files encrypted. Here is the solution: create encrypted filesystem within a file named, say, 16GB.candy.bin that could be stored on regular windows formatted usb flash drive and then mounted under Linux using the password.

When it becomes necessary I can mount that 16GB.candy.bin as the regular ext3 filesystem with all those stuff like permissions, ownership etc. that is available on ext3 but not in FAT or NTFS. On my windows formatted flash drive candy takes only 16 GB so I can use the rest of space to store not so sensitive information like mp3, movies or photos. Moreover I on windows or linux to read it.

Let’s create that 16GB.candy.bin file with encrypted ext3 filesystem (read below explanations below carefully before just to copy/paste commands into CLI):

[root@artemn root]# cd /path/to/candy/

[root@artemn root]# tune2fs -i 0 -c 0 /dev/loop0

Here are some points: using above commands we create encrypted file of 16 GB so if you need to have more or less just change “count=16000″ in dd line. “count=16000″ means 16GB so “count=20″ means 20MB. Path ‘/path/to/candy/’ is for example only so you should change it to real directory that is able to host encrypted file (16 GB in above example). Command losetup is present in most Linux distributions (btw I recommend Ubuntu especially newly released Lucid Lynx) but if it is not use your disro’s packet manager to install it or compile from sources (for super geeks only, Mr. Stallman if you read this article — Hello). Reader, you can replace “/dev/urandom” in dd line with “/dev/zero” that will make that command to finish faster but will lower security level of resulting file (read about AES for better understanding). You will need to enter the password when running losetup command so make sure it safe and long enough like ‘6U2sAsR37Hn8122dGsaPrew1twt’ but not ‘abc123′ or ‘iloveyou’.

Once commands are done you will get 16GB.candy.bin containing encrypted ext3 filesystem. You can store this file where ever you want, say, on a flash drive. If you loose it nobody won’t be able to open it until he (or she!) cracked AES encryption (use long passwords to prevent this). As the next step it is required to mount filesystem and store some files/directories in it:

[root@artemn root]# mkdir -p /mnt/candy

[root@artemn root]# umount /mnt/candy

When you unmount 16GB.candy.bin the changes are already saved there so it’s not required to compress and encrypt anything unlike with GPG.

P.S. This post is inspired by Loopback tricks article. Thanks to the author. Good luck!

0. Install prerequisites:

sudo yum install gcc zlib zlib-devel

1. Download the latest version of Ruby from project’s FTP:

cd /usr/src/
sudo -s
wget ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7.tar.gz
tar -xvzf ruby-1.8.7.tar.gz
cd ruby-1.8.7
./configure --enable-pthread
make
make install

2. Check ruby’s version is 1.8.7:

[root@li110-222 ~]# /usr/local/bin/ruby -v
ruby 1.8.7 (2008-05-31 patchlevel 0) [i686-linux]

That’s it!

Text editors like gedit, emacs, nano or vi will certainly live forever but thankfully there are numerous visual html editors for my Ubuntu They are sometimes called WYSIWYG editors, it mean “What You See Is What You Get”.

1. Quanta Plus

This is KDE/Qt visual html editor available as binary package for numerous Linux distributions
including Debian and Ubuntu. From developers’ site:

Quanta Plus is a highly stable and feature rich web development environment.
The vision with Quanta has always been to start with the best architectural
foundations, design for efficient and natural use and enable maximal user
extensibility.

In order to install it in Debian/Ubuntu run the following CLI command:

sudo apt-get install quanta

Fedora, Centos, Redhat users type this:

sudo yum install kdewebdev

I found Quanta html editor extremely useful, this is just an outstanding application of this
field.

2. Bluefish

Bluefish is a powerful editor targeted towards programmers and webdesigners,
with many options to write websites, scripts and programming code. Bluefish
supports many programming and markup languages, and it focuses on editing
dynamic and interactive websites.

I found this really versatile html editor. Besides HTML/CSS it handles C,
Java, Perl, Python, XML and others.

Ubuntu and Debian users type:

sudo apt-get install bluefish

Fedora/Redhat/Centos:

sudo yum install bluefish

Gentoo:

emerge bluefish

3. Screem

SCREEM is a web development environment. It’s purpose is to increase
productivity when constructing a site, by providing quick access to commonly
used features. While it is written for use with the GNOME desktop environment
in mind it does not specifically require you to be running it, just have the
libraries installed.

This is one of the most user-friendly Gnome HTML editor. Its simple interface
brings extremely powerfull HTML editor so if like minimalistic design Screem
is your choice.

Update: below is the bottom line from Linux.com’s review of three Linux HTML editors (Quanta Plus, Blowfish,
Screem). I found that review after I wrote this post.

• If you use GNOME, use Screem. It’s a fast, simple, and powerful tool for web editing. However, it does not have the large feature sets that Bluefish and Quanta Plus have, especially for languages other than those directly related to Web page editing.
• If you use GNOME and need the more powerful features of Quanta Plus, load the required libraries and run it.
• If you use KDE and want a code editor, choose Quanta Plus. Ignore the WYSIWYG capabilities and take advantage of the tremendous editing capabilities, especially for CSS style sheets.
• If you use Xfce, Quanta Plus should run fine. Screem would still require loading additional libraries.
• Finally, if you use GNOME, find that Screem does not meet all your needs, and you don’t want to bother with loading the KDE-native Quanta Plus, then load Bluefish. It is nearly as capable as Quanta Plus, but will run well without a lot of fussing with libraries.

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]]> http://www.linuxscrew.com/2008/12/23/christmas%e2%80%a6-linux%e2%80%a6-wallpapers%e2%80%a6/feed/ 0 http://www.linuxscrew.com/2008/12/15/open-docx-documents-in-linux-openoffice/ http://www.linuxscrew.com/2008/12/15/open-docx-documents-in-linux-openoffice/#comments Mon, 15 Dec 2008 20:13:23 +0000 artiomix http://www.linuxscrew.com/?p=623 Well, as for now it is not a problem anymore to open Microsoft Office 2007 .docx documents in any Linux distribution coming with OpenOffice suit. It may be Ubuntu (Feisty, Gutsy, Interpid whatever), almost any version of Fedora/RedHat/Centos, *SUSE, Mandriva and of course Debian (as per my personal opinion it’s the best one).

What is .docx actually? It’s Microsoft’s file format representing word processor documents and named OpenXML (as an attempt to create open and free international standard). Today .docx is default format for Microsoft’s word processor Word.

There are myriads of online converters between OpenXML and OpenOffice formats including .docx, .xlsx, .odt and many etc but sometimes it’s much more better to just open received .docx file in Linux offline (if there is temporarily no Internet connection or for security/private reasons etc).

So, just download the following package to certain directory like /usr/src, here are the commands to do it:

1. cd /usr/src
2. sudo wget http://blog.mypapit.net/imej/odf_filter.tar.bz2

The next step is to unpack the contents of the archive (.tar.bz2 is definitely well compressed file) and copy 3 files to OpenOffice’s system directories:

3. sudo tar -xvjf odf_filter.tar.bz2
4. sudo cp OdfConverter /usr/lib/openoffice/program/
5. sudo cp MOOXTypeDetection.xcu /usr/lib/openoffice/share/registry/modules/org/openoffice/TypeDetection/Types/
6. sudo cp MOOXFilter_cpp.xcu /usr/lib/openoffice/share/registry/modules/org/openoffice/TypeDetection/Filter/

As you can see from picture below now it’s possible to natively open .docx files in openoffice under Linux. Of course such “native” support may imply some artefacts in opened files due to file formats incompatibility so it’s also a good option to ask your friends to convert .docs into .pdf before sending you

P.S. Thanks to guys from mypapit.

P.S. Here are several online converters .doc(x) <-> .odf <-> .pdf:

1. ZAMZAR (possibly the best converter), 2. http://docx-converter.com/.

1. mplayer (sudo aptitude install mplayer)
2. lame (sudo aptitude install lame)
3. win32 codecs (sudo aptitude install ubuntu-restricted-extras)

and then convert file.wma into file.mp3 using the following console command:

mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader file.wma;lame -m s -V 3 audiodump.wav;mv audiodump.wav.mp3 file.mp3;rm audiodump.wav

This also works for Fedora / Centos / Redhat family Linux distributions (requirements should be installed by yum package manager via third-party software repositories).

Well, after quick testings there are no doubts that it is not a good option if you wish to have quick and stable alternative for Firefox… But of course it is good for evaluation purposes or for those people who CAN’T wait for official release of Chrome for Linux Certainly the port is based on Windows copy run by Wine (don’t forget to upgrade it). Actually CodeWeavers says that this is just a proof of concept, for fun, and to showcase what Wine can do.

Another application of checkinstall is software deinstallation that was compiled and installed from sources. As you might already noticed, not every programmer adds “uninstall” rule to Makefile and thus command “make uninstall” would fail. The nice solution is to use checkinstall to prepare binary package from sources and then install or uninstall it with dpkg command (or rpm in RedHat based distributions).

Here is the short algorithm on how to prepare .deb package from clamav source tarball:

1. Install checkinstall:
sudo aptitude -y install checkinstall (Ubuntu, Debian and related distributions)
or
sudo yum install -y checkinstall
(for rpm based distributions, please note that checkinstall usually isn’t included to standard Fedora/RedHat repositories, so you will need to link up third party repo like DAG)
or
compile checkinstall from sources

2. Get clamav sources:
wget http://mesh.dl.sourceforge.net/sourceforge/clamav/clamav-0.81.tar.gz (as an example)

3. Install libraries that might be necessary for clamav compilation:
sudo aptitude install libgmp3 libgmp3-dev
(this command is applicable for Debian and certainly will be different for Fedora or RedHat)

4. Compile clamav:
tar xvfz clamav-0.81.tar.gz
cd clamav-0.81/
./configure --sysconfdir=/etc
make

5. Run checkinstall and follow its intuitive instructions (enter package description etc.):
sudo checkinstall -D make install

6. When finished you’ll get clamav-0.81_0.81-1_i386.deb (or rpm package if you use Fedora/RedHat/CentOs) you may want to install with sudo dpkg -i clamav-0.81_0.81-1_i386.deb (or sudo rpm -i ...) or move to another PC for later installation.