Posts Tagged ‘tutorial’

How to install Samsung ML-2010 (ML-2010P) Mono Laser Printer on Xubuntu GNU/Linux

Wednesday, January 18th, 2012

I had to make one old Samsung ML-2010P Laser Printer work on Xubuntu Linux . I've had some issues in installing it, I couldn't fine any step by step tutorial online, on how the printer can be made work fine on Linux. Therefore I took the time to experiment and see if I could make it work. Since the printer is old, not much people are interested any more in making the printer operational on Linux, hence I couldn't find too much relevant posts and sites on the net, anyways thanks God after a bit of pondering I finally succeeded to make the Samsung ML-2010P printer to print on Linux.This are the exact steps one has to follow to make this old bunch of hardware to play nice on Linux:

1. use lsusb to list the printer model

root@linux:~# lsusb |grep -i samsung
Bus 001 Device 003: ID 04e8:326c Samsung Electronics Co., Ltd ML-2010P Mono Laser Printer

You see the printer reports as Samsung Electronics Co., Ltd ML-2010P Mono Laser Printer

2. Install cups printing service required packages

root@linux:~# apt-get install cups cups-bsd cups-client cups-common
root@linux:~# apt-get install cups-driver-gutenprint ghostscript-cups
root@linux:~# apt-get install python-cups python-cupshelpers

3. Install foomatic packages

root@linux:~# apt-get install foomatic-db foomatic-db-engine foomatic-db-gutenprint
root@linux:~# apt-get install foomatic-filters python-foomatic

4. Install hpijs hplip printconfand other packages necesssery for proper printer operation

root@linux:~# apt-get install hpijs hplip hplip-data ijsgutenprint
root@linux:~# apt-get install min12xxw openprinting-pdds printconf foo2zjs

P.S. Some of the packages I list might already have been installed as a dependency to another package, as I'm writting this article few days after I've succeeded installing the printer, I don't remember the exact install order.

5. Install splix (SPL Driver for Unix)

Here is a quote taken from Spix's project website:

"SpliX is a set of CUPS printer drivers for SPL (Samsung Printer Language) printers.
If you have a such printer, you need to download and use SpliX. Moreover you will find documentation about this proprietary language.
"

root@linux:~# apt-get install splix

For more information on splix, check on Splix SPL driver for UNIX website http://splix.ap2c.org/

You can check on the projects website the Samsung ML 2010 Printer is marked as Working
Next step is to configure the Printer

6. Go to Cups interface on localhost in browser and Add the Samsung printer.

Use Firefox, SeaMonkey or any browser of choice to configure CUPS:

Type in the browser:

http://localhost:631

Next a password prompt will appear asking for a user/pass. The user/pass you have to use is the same as the password of the user account you're logged on with.

UNIX Linux Administration CUPS Printer adding Samsung ML 2010 ML-2010P Xubuntu

Click on the Add Printer button and choose to add the Samsung ML-2010.

Then restart the CUP Service (cupsd) to make it load the new settings:

root@linux:~# /etc/init.d/cups restart

Now give the printer a try in printing some page in SeaMonkey, Chrome or Firefox (the quickest way is through pressing CTRL + P )

Following this steps, I've managed to run the printer on Xubuntu Linux, though the same steps if followed should most probably make the Samsnung ML 2010 play nice with other Linux distributions with a little or no adjustments.
I'll be glad to hear if someone succeeded in making the printer work on other distributions, if so please drop me a comment.
That's all folks! Enjoy printing 😉

Install jwchat web chat jabber interface to work with Debian ejabberd jabber server

Wednesday, January 4th, 2012

JWChat ejabber jabber Ajax / HTML based client logo
 

I have recently blogged how I've installed & configured ejabberd (jabber server) on Debian .
Today I decided to further extend, my previous jabberd installation by installing JWChat a web chat interface frontend to ejabberd (a good substitute for a desktop app like pidgin which allows you to access a jabber server from anywhere)

Anyways for a base of installing JWChat , I used the previously installed debian deb version of ejabberd from the repositories.

I had a lot of troubles until I actually make it work because of some very minor mistakes in following the official described tutorial ejabberd website jwchat install tutorual

The only way I can make jwchat work was by using the install jwchat with ejabberd's HTTP-Bind and file server method

Actually for quite a long time I was not realizing that, there are two ways to install JWChat , so by mistake I was trying to mix up some install instructions from both jwchat HTTP-Bind file server method and JWchat Apache install method

I've seen many people complaining on the page of Install JWChat using Apache method which seemed to be experiencing a lot of strangle troubles just like the mines when I mixed up the jwchat php scripts install using instructions from both install methods. Therefore my guess is people who had troubles in installing using the Apache method and got the blank page issues while accessing http://jabber.servername.com:5280/http-poll/ as well as various XML Parsing Error: no element found errors on – http://ejabberd.oac.com:5280/http-poll/ is most probably caused by the same install instructions trap I was diluted in.

The steps to make JWChat install using the HTTP-Bind and file server method, if followed should be followed absolutely precisely or otherwise THEY WILL NOT WORK!!!

This are the exact steps I followed to make ejabberd work using the HTTP-Bind file server method :

1. Create directory to store the jwchat Ajax / htmls

debian:~# mkdir /var/lib/ejabberd/www
debian:~# chmod +x /var/lib/ejabberd
debian:~# chmod +x /var/lib/ejabberd/www

2. Modify /etc/ejabberd/ejabberd.cfg and include the following configs

While editting the conf find the section:

{listen,
[


Scrolling down you will fine some commented code marked with %% that will read:

{5269, ejabberd_s2s_in, [
{shaper, s2s_shaper},
{max_stanza_size, 131072}
]},

Right after it leave one new line and place the code:

{5280, ejabberd_http, [
{request_handlers, [
{["web"], mod_http_fileserver}
]},

http_bind,
http_poll,
web_admin
]}
]}.

Scrolling a bit down the file, there is a section which says:

%%% =======
%%% MODULES

%%
%% Modules enabled in all ejabberd virtual hosts.
%%

The section below the comments will look like so:

{modules, [ {mod_adhoc, []},
{mod_announce, [{access, announce}]}, % requires mod_adhoc
{mod_caps, []},
{mod_configure,[]}, % requires mod_adhoc
{mod_ctlextra, []},
{mod_disco, []},
%%{mod_echo, [{host, "echo.localhost"}]},
{mod_irc, []},
{mod_last, []},

After the {mod_last, … the following lines should be added:

{mod_http_bind, []},
{mod_http_fileserver, [
{docroot, "/var/lib/ejabberd/www"},
{accesslog, "/var/log/ejabberd/webaccess.log"}
]},

3. Download and extract latest version of jwchat

Of the time of writting the latest version of jwchat is jwchat-1.0 I have mirrored it on pc-freak for convenience:

debian:~# wget http://www.pc-freak.net/files/jwchat-1.0.tar.gz
….

debian:~# cd /var/lib/ejabberd/www
debian:/var/lib/ejabberd/www# tar -xzvf jwchat-1.0.tar.gz
...
debian:/var/lib/ejabberd/www# mv jwchat-1.0 jwchat
debian:/var/lib/ejabberd/www# cd jwchat

4. Choose the language in which you will prefer jwchat web interface to appear

I prefer english as most people would I suppose:

debian:/var/lib/ejabberd/www/jwchat# for a in $(ls *.en); do b=${a%.en}; cp $a $b; done

For other languages change in the small one liner shell script b=${a%.en} (en) to whatever language you will prefer to make primary.After selecting the correct langauge a rm cmd should be issued to get rid of the .js.* and .html.* in other language files which are no longer needed:

debian:/var/lib/ejabberd/www/jwchat# rm *.html.* *.js.*

5. Configure JWChat config.js

Edit /var/lib/ejabberd/www/jwchat/config.js , its necessery to have inside code definitions like:

/* If your Jabber server is jabber.example.org, set this: */
var SITENAME = "jabber.example.org";

/* If HTTP-Bind works correctly, you may want do remove HTTP-Poll here */
var BACKENDS =
[
{
name:"Native Binding",
description:"Ejabberd's native HTTP Binding backend",
httpbase:"/http-bind/",
type:"binding",
servers_allowed:[SITENAME]
}
];

6. Restart EJabberd server to load the new config settings

debian:~# /etc/init.d/ejabberd restart
Restarting jabber server: ejabberd..

7. Test JWChat HTTP-Bind and file server backend

I used elinksand my beloved Epiphany (default gnome browser) which by the way is the browser I use daily to test that the JWChat works fine with the ejabberd.
To test the newly installed HTTP-Bind ejabberd server backend on port 5280 I used URL:

http://jabber.mydomain.com:5280/web/jwchat/I had quite a struggles with 404 not found errors, which I couldn't explain for half an hour. After a thorough examination, I've figured out the reasons for the 404 errors was my stupidity …
The URL http://jabber.mydomain.com:5280/web/jwchat/ was incorrect because I fogrot to move jwchat-1.0 to jwchat e.g. (mv jwchat-1.0 jwchat) earlier explained in that article was a step I missed. Hence to access the web interface of the ejabberd without the 404 error I had to access it via:

http://jabber.mydomain.com:5280/web/jwchat-1.0

JWChat Ejabber webchat Epiphany Linux screenshot

Finally it is handy to add a small index.php redirect to redirect to http://jabber.mydomain.com:5280/web/jwchat-1.0/

The php should like so:


<?
php
header( 'Location: http://jabber.mydomain.com:5280/web/jwchat-1.0' ) ;
?>

How to make GRE tunnel iptables port redirect on Linux

Saturday, August 20th, 2011

I’ve recently had to build a Linux server with some other servers behind the router with NAT.
One of the hosts behind the Linux router was running a Window GRE encrypted tunnel service. Which had to be accessed with the Internet ip address of the server.
In order < б>to make the GRE tunnel accessible, a bit more than just adding a normal POSTROUTING DNAT rule and iptables FORWARD is necessery.

As far as I’ve read online, there is quite of a confusion on the topic of how to properly configure the GRE tunnel accessibility on Linux , thus in this very quick tiny tutorial I’ll explain how I did it.

1. Load the ip_nat_pptp and ip_conntrack_pptp kernel module

linux-router:~# modprobe ip_nat_pptp
linux-router:~# modprobe ip_conntrack_pptp

These two modules are an absolutely necessery to be loaded before the remote GRE tunnel is able to be properly accessed, I’ve seen many people complaining online that they can’t make the GRE tunnel to work and I suppose in many of the cases the reason not to be succeed is omitting to load this two kernel modules.

2. Make the ip_nat_pptp and ip_nat_pptp modules to load on system boot time

linux-router:~# echo 'ip_nat_pptp' >> /etc/modules
linux-router:~# echo 'ip_conntrack_pptp' >> /etc/modules

3. Insert necessery iptables PREROUTING rules to make the GRE tunnel traffic flow

linux-router:~# /sbin/iptables -A PREROUTING -d 111.222.223.224/32 -p tcp -m tcp --dport 1723 -j DNAT --to-destination 192.168.1.3:1723
linux-router:~# /sbin/iptables -A PREROUTING -p gre -j DNAT --to-destination 192.168.1.3

In the above example rules its necessery to substitute the 111.222.223.224 ip address withe the external internet (real IP) address of the router.

Also the IP address of 192.168.1.3 is the internal IP address of the host where the GRE host tunnel is located.

Next it’s necessery to;

4. Add iptables rule to forward tcp/ip traffic to the GRE tunnel

linux-router:~# /sbin/iptables -A FORWARD -p gre -j ACCEPT

Finally it’s necessery to make the above iptable rules to be permanent by saving the current firewall with iptables-save or add them inside the script which loads the iptables firewall host rules.
Another possible way is to add them from /etc/rc.local , though this kind of way is not recommended as rules would add only after succesful bootup after all the rest of init scripts and stuff in /etc/rc.local is loaded without errors.

Afterwards access to the GRE tunnel to the local IP 192.168.1.3 using the port 1723 and host IP 111.222.223.224 is possible.
Hope this is helpful. Cheers 😉

How to Split files on Linux FreeBSD, NetBSD and OpenBSD

Sunday, July 31st, 2011

Split large files in pieces Scissors

Did you have the need to sometimes split an SQL extra large files to few pieces in order to be able to later upload it via phpmyadmin?
Did you needed an extra large video or data file to be cut in few pieces in order to transfer it in few pieces over an USB stick?
Or just to give you an another scenario where I sometimes need to have an enormous file let’s say 3G split in few pieces, in order to later read it in vim or mcedit .
I sometimes need to achieve this on FreeBSD and Linux hosts thus I thought it will be helpful to somebody to give a very quick tutorial on the way large files can be cut in pieces on Linux and BSD hosts.

GNU/Linux and FreeBSD are equipped with the split command. The purpose of this command is exactly the cutting of a file to a number of pieces.

On Linux the split command comes by default install to the system with the coreutils package on most Debian (deb) based and Redhat based (rpm) distributions, theerefore Linux’s version of split is GNU/split since it’s part of the GNU Coreutils package. An interesting fact about Linux split is that one of the two programmers who has coded it is Richard Stallman 😉

On BSD Unix split is the AT&T UNIX (BSD) split

In the past splitting files in pieces was much more needed than today, as people used floppy drives to transfer data, though today with the bloom of Internet and the improve of the data carriers transferring even an extra large files from one place to another is a way more trivial task still at many occasions splitting it in pieces is needed.

Even though today splitting file is very rarely required, still there are times when being able to split a file in X number of parts is very much needed.
Maybe the most common use of splitting a file today is necessery when a large SQL file dumps, like let’s say 200 MBytes of info database needs to be moved from ane hosting provider to another one.
Many hosting providers does disallow direct access with standard mySQL client programs to the database directly and only allow a user to connect only via phpMyAdmin or some other web interface like Cpanel to improve data into the SQL or PostgreSQL server.

In such times, having knowledge on the Unix split command is a priceless asset.

Even though on Linux and BSD the code for the split command is not identical and GNU/split and BSD/split has some basic differences, the use of split on both of these Unices is identical.
The way to split a file in few pieces using on both Linux and BSD OSes is being done with one and the same command, here is how:

1. Splitting file in size of 40 mb On Linux

linux:~# split -b 40m SQL-Backup-Data.sql SQL-Backup-Data_split

2. Splitting file in size of 40mb on BSD (FreeBSD, OpenBSD, NetBSD)

freebsd# split -b 40m SQL-Backup-Data.sql SQL-Backup-Data_split

The Second argument the split command takes is actually called a prefix, the prefix is used as a basis name for the creation of the newly generated files cut in pieces file based on SQL-Backup-Data.sql.

As I said identical command will split the SQL-Backup-Data.sql files in a couple of parts which of it will be sized 40 megas.

These command will generate few files output like:

freebsd# ls -1 SQL-Backup-Dat*SQL-Backup-Data.sql
SQL-Backup-Dataa
SQL-Backup-Dataab
SQL-Backup-Dataac
SQL-Backup-Dataad
SQL-Backup-Dataae

As you see the SQL-Backup-Data.sql with size 200MB is being split in four files each of which is sized 40mbytes.

After the files are transfered to another Linux or BSD host, they can easily be again united in the original file with the command:

linux:~# for i in $(ls -1 SQL-Backup-Data_split*); echo $i >> SQL-Backup-Data.sql

Alternatively in most Unices also using cat should be enough to collect back the pieces into the original file, like so:

freebsd# cat SQL-Backup-Data_split* >> SQL-Backup-Data.sql

Enjoy splitting

Sys Admin VIM Quick Cheat Sheet ! ;)

Wednesday, July 20th, 2011

Have you, ever thought of refreshing your VIM knowledge obtained back in the days reading the vimtutorial available straight in vim via the:
vimtutor comand?

I asked few vim related question today in #vim in irc freenode and I was referred to one mate to the following picture:

Vi VIM Tutorial Quick Cheat Sheet

VIM QUICK Tutorial Sheet Picture ! 😉 Nice ! Aint’t it? 🙂

xorg on Toshiba Satellite L40 14B with Intel GM965 video hangs up after boot and the worst fix ever / How to reinstall Ubuntu by keeping the old personal data and programs

Wednesday, April 27th, 2011

black screen ubuntu troubles

I have updated Ubuntu version 9.04 (Jaunty) to 9.10 and followed the my previous post update ubuntu from 9.04 to Latest Ubuntu

I expected that a step by step upgrade from a release to release will work like a charm and though it does on many notebooks it doesn't on Toshiba Satellite L40

The update itself went fine, whether I used the update-manager -d and followed the above pointed tutorial, however after a system restart the PC failed to boot the X server properly, a completely blank screen with blinking cursor appeared and that was all.

I restarted the system into the 2.6.35-28-generic kernel rescue-mode recovery kernel in order to be able to enter into physical console.

Logically the first thing I did is to check /var/log/messages and /var/log/Xorg.0.log but I couldn't find nothing unusual or wrong there.

I suspected something might be wrong with /etc/X11/xorg.conf so I deleted it:

ubuntu:~# rm -f /etc/X11/xorg.conf

and attempted to re-create the xorg.conf X configuration with command:

ubuntu:~# dpkg-reconfigure xserver-xorg

This command was reported to be the usual way to reconfigure the X server settings from console, but in my case (for unknown reasons) it did nothing.

Next the command which was able to re-generate the xorg.conf file was:

ubuntu:~# X -configure

The command generates a xorg.conf sample file in /root/xorg.conf.* so I used the conf to put it in /etc/X11/xorg.conf X's default location and restarted in hope that this would fix the non-booting issue.

Very sadly again the black screen of death appeared on the notebook toshiba screen.
I further thought of completely wipe out the xorg.conf in hope that at least it might boot without the conf file but this worked out neither.

I attempted to run the Xserver with a xorg.conf configured to work with vesa as it's well known vesa X server driver is supposed to work on 99% of the video cards, as almost all of them nowdays are compatible with the vesa standard, but guess what in my case vesa worked not!

The only version of X I can boot in was the failsafe X screen mode which is available through the grub's boot menu recovery mode.

Further on I decided to try few xorg.conf which I found online and were reported to work fine with Intel GM965 internal video , and yes this was also unsucessful.

Some of my other futile attempts were: to re-install the xorg server with apt-get, reinstall the xserver-xorg-video-intel driver e.g.:

ubuntu:~# apt-get install --reinstall xserver-xorg xserver-xorg-video-intel

As nothing worked out I was completely pissed off and decided to take an alternative approach which will take a lot of time but at least will probably be succesful, I decided to completely re-install the Ubuntu from a CD after backing up the /home directory and making a list of available packages on the system, so I can further easily run a tiny bash one-liner script to install all the packages which were previously existing on the laptop before the re-install:

Here is how I did it:

First I archived the /home directory:

ubuntu:/# tar -czvf home.tar.gz home/
....

For 12GB of data with some few thousands of files archiving it took about 40 minutes.

The tar spit archive became like 9GB and I hence used sftp to upload it to a remote FTP server as I was missing a flash drive or an external HDD where I can place the just archived data.

Uploading with sftp can be achieved with a command similar to:

sftp user@yourhost.com
Password:
Connected to yourhost.com.
sftp> put home.tar.gz

As a next step to backup in a file the list of all current installed packages, before I can further proceed to boot-up with the Ubuntu Maverich 10.10 CD and prooceed with the fresh install I used command:

for i in $(dpkg -l| awk '{ print $2 }'); do
echo $i; done >> my_current_ubuntu_packages.txt

Once again I used sftp as in above example to upload my_current_update_packages.txt file to my FTP host.

After backing up all the stuff necessery, I restarted the system and booted from the CD-rom with Ubuntu.
The Ubuntu installation as usual is more than a piece of cake and even if you don't have a brain you can succeed with it, so I wouldn't comment on it 😉

Right after the installation I used the sftp client once again to fetch the home.tar.gz and my_current_ubuntu_packages.txt

I placed the home.tar.gz in /home/ and untarred it inside the fresh /home dir:

ubuntu:/home# tar -zxvf home.tar.gz

Eventually the old home directory was located in /home/home so thereon I used Midnight Commander ( the good old mc text file explorer and manager ) to restore the important user files to their respective places.

As a last step I used the my_current_ubuntu_packages.txt in combination with a tiny shell script to install all the listed packages inside the file with command:

ubuntu:~# for i in $(cat my_current_ubuntu_packagespackages.txt); do
apt-get install --yes $i; sleep 1;
done

You will have to stay in front of the computer and manually answer a ncurses interface questions concerning some packages configuration and to be honest this is really annoying and time consuming.

Summing up the overall time I spend with this stupid Toshiba Satellite L40 with the shitty Intel GM965 was 4 days, where each day I tried numerous ways to fix up the X and did my best to get through the blank screen xserver non-bootable issue, without a complete re-install of the old Ubuntu system.
This is a lesson for me that if I stumble such a shitty issues I will straight proceed to the re-install option and not loose my time with non-sense fixes which would never work.

Hope the article might be helpful to somebody else who experience some problems with Linux similar to mine.

After all at least the Ubuntu Maverick 10.10 is really good looking in general from a design perspective.
What really striked me was the placement of the close, minimize and maximize window buttons , it seems in newer Ubuntus the ubuntu guys decided to place the buttons on the left, here is a screenshot:

Left button positioning of navigation Buttons in Ubuntu 10.10

I believe the solution I explain, though very radical and slow is a solution that would always work and hence worthy 😉
Let me hear from you if the article was helpful.

How to automatically reboot (restart) Debian GNU Lenny / Squeeze Linux on kernel panic, some general CPU overload or system crash

Monday, June 21st, 2010

If you are a system administrator, you have probably wondered at least once ohw to configure your Linux server to automatically reboot itself if it crashes, is going through a mass CPU overload, e.g. the server load average “hits the sky”.
I just learned from a nice article found here that there is a kernel variable which when enabled takes care to automatically restart a crashed server with the terrible Kernel Panic message we all know.

The variable I’m taking about is kernel.panic for instance kernel.panic = 20 would instruct your GNU Linux kernel to automatically reboot if it experiences a kernel panic system crash within a time limit of 20 seconds.

To start using the auto-reboot linux capabilities on a kernel panic occurance just set the variable to /etc/sysctl.conf

debian-server:~# echo 'kernel.panic = 20' >> /etc/sysctl.conf

Now we will also have to enable the variable to start being use on the system, so execute:

debian-server:~# sysctl -p There you go automatic system reboots on kernel panics is now on.
Now to further assure yourself the linux server you’re responsible of will automatically restart itself on a emergency situation like a system overload I suggest you check Watchdog

You might consider checking out this auto reboot tutorial which explains in simple words how watchdog is installed and configured.
On Debian installing and maintaining watchdog is really simple and comes to installing and enabling the watchdog system service, right afteryou made two changes in it’s configuration file /etc/watchdog.conf

To do so execute:

debian-server:~# apt-get install watchdog
debian-server:~# echo "file = /var/log/messages" >> /etc/watchdog.conf
debian-server:~# echo "watchdog-device = /dev/watchdog" >> /etc/watchdog.conf

Well that should be it, you might also need to load some kernel module to monitor your watchdog.
On my system the kernel modules related to watchdog are located in:

/lib/modules/2.6.26-2-amd64/kernel/drivers/watchdog/
If not then you should certainly try the software watchdog linux kernel module called softdog , to do so issue:
debian-server:~# /sbin/modprobe softdog

It’s best if you load the module while the softdog daemon is disabled.
If you consider auto loadig the softdog software watchdog kernel driver you should exec:

debian-server:~# echo 'softdog' >> /etc/modules

Finally a start of the watchdog is necessery:

 


debian-server:~# /etc/init.d/watchdog start
Stopping watchdog keepalive daemon....
Starting watchdog daemon....

That should be all your automatic system reboots should be now on! 🙂