Posts Tagged ‘code’

Tiny PHP script to dump your browser set HTTP headers (useful in debugging)

Friday, March 30th, 2012

While browsing I stumbled upon a nice blog article

Dumping HTTP headers

The arcitle, points at few ways to DUMP the HTTP headers obtained from user browser.
As I'm not proficient with Ruby, Java and AOL Server what catched my attention is a tiny php for loop, which loops through all the HTTP_* browser set variables and prints them out. Here is the PHP script code:

<?php<br />
foreach($_SERVER as $h=>$v)<br />
if(ereg('HTTP_(.+)',$h,$hp))<br />
echo "<li>$h = $v</li>\n";<br />
header('Content-type: text/html');<br />
?>

The script is pretty easy to use, just place it in a directory on a WebServer capable of executing php and save it under a name like:
show_HTTP_headers.php

If you don't want to bother copy pasting above code, you can also download the dump_HTTP_headers.php script here , rename the dump_HTTP_headers.php.txt to dump_HTTP_headers.php and you're ready to go.

Follow to the respective url to exec the script. I've installed the script on my webserver, so if you are curious of the output the script will be returning check your own browser HTTP set values by clicking here.
PHP will produce output like the one in the screenshot you see below, the shot is taken from my Opera browser:

Screenshot show HTTP headers.php script Opera Debian Linux

Another sample of the text output the script produce whilst invoked in my Epiphany GNOME browser is:

HTTP_HOST = www.pc-freak.net
HTTP_USER_AGENT = Mozilla/5.0 (X11; U; Linux x86_64; en-us) AppleWebKit/531.2+ (KHTML, like Gecko) Version/5.0 Safari/531.2+ Debian/squeeze (2.30.6-1) Epiphany/2.30.6
HTTP_ACCEPT = application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
HTTP_ACCEPT_ENCODING = gzip
HTTP_ACCEPT_LANGUAGE = en-us, en;q=0.90
HTTP_COOKIE = __qca=P0-2141911651-1294433424320;
__utma_a2a=8614995036.1305562814.1274005888.1319809825.1320152237.2021;wooMeta=MzMxJjMyOCY1NTcmODU1MDMmMTMwODQyNDA1MDUyNCYxMzI4MjcwNjk0ODc0JiYxMDAmJjImJiYm; 3ec0a0ded7adebfeauth=22770a75911b9fb92360ec8b9cf586c9;
__unam=56cea60-12ed86f16c4-3ee02a99-3019;
__utma=238407297.1677217909.1260789806.1333014220.1333023753.1606;
__utmb=238407297.1.10.1333023754; __utmc=238407297;
__utmz=238407297.1332444980.1586.413.utmcsr=www.pc-freak.net|utmccn=(referral)|utmcmd=referral|utmcct=/blog/

You see the script returns, plenty of useful information for debugging purposes:
HTTP_HOST – Virtual Host Webserver name
HTTP_USER_AGENT – The browser exact type useragent returnedHTTP_ACCEPT – the type of MIME applications accepted by the WebServerHTTP_ACCEPT_LANGUAGE – The language types the browser has support for
HTTP_ACCEPT_ENCODING – This PHP variable is usually set to gzip or deflate by the browser if the browser has support for webserver returned content gzipping.
If HTTP_ACCEPT_ENCODING is there, then this means remote webserver is configured to return its HTML and static files in gzipped form.
HTTP_COOKIE – Information about browser cookies, this info can be used for XSS attacks etc. 🙂
HTTP_COOKIE also contains the referrar which in the above case is:
__utmz=238407297.1332444980.1586.413.utmcsr=www.pc-freak.net|utmccn=(referral)
The Cookie information HTTP var also contains information of the exact link referrar:
|utmcmd=referral|utmcct=/blog/

For the sake of comparison show_HTTP_headers.php script output from elinks text browser is like so:

* HTTP_HOST = www.pc-freak.net
* HTTP_USER_AGENT = Links (2.3pre1; Linux 2.6.32-5-amd64 x86_64; 143x42)
* HTTP_ACCEPT = */*
* HTTP_ACCEPT_ENCODING = gzip,deflate * HTTP_ACCEPT_CHARSET = us-ascii, ISO-8859-1, ISO-8859-2, ISO-8859-3, ISO-8859-4, ISO-8859-5, ISO-8859-6, ISO-8859-7, ISO-8859-8, ISO-8859-9, ISO-8859-10, ISO-8859-13, ISO-8859-14, ISO-8859-15, ISO-8859-16, windows-1250, windows-1251, windows-1252, windows-1256,
windows-1257, cp437, cp737, cp850, cp852, cp866, x-cp866-u, x-mac, x-mac-ce, x-kam-cs, koi8-r, koi8-u, koi8-ru, TCVN-5712, VISCII,utf-8 * HTTP_ACCEPT_LANGUAGE = en,*;q=0.1
* HTTP_CONNECTION = keep-alive
One good reason, why it is good to give this script a run is cause it can help you reveal problems with HTTP headers impoperly set cookies, language encoding problems, security holes etc. Also the script is a good example, for starters in learning PHP programming.

 

FreeBSD Jumbo Frames network configuration short how to

Wednesday, March 14th, 2012

FreeBSD Jumbo Frames Howto configure FreeBSD

Recently I wrote a post on how to enable Jumbo Frames on GNU / Linux , therefore I thought it will be useful to write how Jumbo Frames network boost can be achieved on FreeBSD too.

I will skip the details of what is Jumbo Frames, as in the previous article I have thoroughfully explained. Just in short to remind you what is Jumbo Frames and why you might need it? – it is a way to increase network MTU transfer frames from the MTU 1500 to MTU of 9000 bytes

It is interesting to mention that according to specifications, the maximum Jumbo Frames MTU possible for assignment are of MTU=16128
Just like on Linux to be able to take advantage of the bigger Jumbo Frames increase in network thoroughput, you need to have a gigabyt NIC card/s on the router / server.

1. Increasing MTU to 9000 to enable Jumbo Frames "manually"

Just like on Linux, the network tool to use is ifconfig. For those who don't know ifconfig on Linux is part of the net-tools package and rewritten from scratch especially for GNU / Linux OS, whether BSD's ifconfig is based on source code taken from 4.2BSD UNIX

As you know, network interface naming on FreeBSD is different, as there is no strict naming like on Linux (eth0, eth1, eth2), rather the interfaces are named after the name of the NIC card vendor for instance (Intel(R) PRO/1000 NIC is em0), RealTek is rl0 etc.

To set Jumbro Frames Maximum Transmission Units of 9000 on FreeBSD host with a Realtek and Intel gigabyt ethernet cards use: freebsd# /sbin/ifconfig em0 192.168.1.2 mtu 9000
freebsd# /sbin/ifconfig rl0 192.168.2.2 mtu 9000

!! Be very cautious here, as if you're connected to the system remotely over ssh you might loose connection to it because of broken routing.

To prevent routing loss problems, if you're executing the above two commands remotely, you better run them in GNU screen session:

freebsd# screen
freebsd# /sbin/ifconfig em0 192.168.1.2 mtu 9000; /sbin/ifconfig rl0 192.168.1.2 mtu 9000; \
/etc/rc.d/netif restart; /etc/rc.d/routed restart

2. Check MTU settings are set to 9000

If everything is fine the commands will return empty output, to check further the MTU is properly set to 9000 issue:

freebsd# /sbin/ifconfig -a|grep -i em0em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 9000freebsd# /sbin/ifconfig -a|grep -i rl0
rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 9000

3. Reset routing for default gateway

If you have some kind of routing assigned for em0 and rl0, network interfaces they will be affected by the MTU change and the routing will be gone. To reset the routing to the previously properly assigned routing, you have to restart the BSD init script taking care for assigning routing on system boot time:

freebsd# /etc/rc.d/routing restart
default 192.168.1.1 done
add net default: gateway 192.168.1.1
Additional routing options: IP gateway=YES.

4. Change MTU settings for NIC card with route command

There is also a way to assign higher MTU without "breaking" the working routing, e.g. avoiding network downtime with bsd route command:

freebsd# grep -i defaultrouter /etc/rc.conf
defaultrouter="192.168.1.1"
freebsd# /sbin/route change 192.168.1.1 -mtu 9000
change host 192.168.1.1

5. Finding the new MTU NIC settings on the FreeBSD host

freebsd# /sbin/route -n get 192.168.1.1
route to: 192.168.1.1
destination: 192.168.1.1
interface: em0
flags: <UP,HOST,DONE,LLINFO,WASCLONED>
recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire
0 0 0 0 0 0 9000 1009

6. Set Jumbo Frames to load automatically on system load

To make the increased MTU to 9000 for Jumbo Frames support permanent on a FreeBSD system the /etc/rc.conf file is used:

The variable for em0 and rl0 NICs are ifconfig_em0 and ifconfig_rl0.
The lines to place in /etc/rc.conf should be similar to:

ifconfig_em0="inet 192.168.1.1 netmask 255.255.255.0 media 1000baseTX mediaopt half-duplex mtu 9000"
ifconfig_em0="inet 192.168.1.1 netmask 255.255.255.0 media 1000baseTX mediaopt half-duplex mtu 9000"

Change in the above lines the gateway address 192.168.1.1 and the netmask 255.255.255.0 to yours corresponding gw and netmask.
Also in the above example you see the half-duplex ifconfig option is set insetad of full-duplex in order to prevent some duplex mismatches. A full-duplex could be used instead, if you're completely sure on the other side of the host is configured to support full-duplex connections. Otherwise if you try to set full-duplex with other side set to half-duplex or auto-duplex a duplex mismatch will occur. If this happens insetad of taking the advantage of the Increase Jumbo Frames MTU the network connection could become slower than originally with standard ethernet MTU of 1500. One other bad side if you end up with duplex-mismatch could be a high number of loss packets and degraded thoroughout …

7. Setting Jumbo Frames for interfaces assigning dynamic IP via DHCP

If you need to assign an MTU of 9000 for a gigabyt network interfaces, which are receiving its TCP/IP network configuration over DHCP server.
First, tell em0 and rl0 network interfaces to dynamically assign IP addresses via DHCP proto by adding in /etc/rc.conf:

ifconfig_em0="DHCP"
ifconfig_rl0="DHCP"

Secondly make two files /etc/start_if.em0 and /etc/start_if.rl0 and include in each file:

ifconfig em0 media 1000baseTX mediaopt full-duplex mtu 9000
ifconfig rl0 media 1000baseTX mediaopt full-duplex mtu 9000

Copy / paste in root console:

echo 'ifconfig em0 media 1000baseTX mediaopt full-duplex mtu 9000' >> /etc/start_if.em0
echo 'ifconfig rl0 media 1000baseTX mediaopt full-duplex mtu 9000' >> /etc/start_if.rl0

Finally, to load the new MTU for both interfaces, reload the IPs with the increased MTUs:

freebsd# /etc/rc.d/routing restart
default 192.168.1.1 done
add net default: gateway 192.168.1.1

8. Testing if Jumbo Frames is working correctly

To test if an MTU packs are transferred correctly through the network you can use ping or tcpdumpa.) Testing Jumbo Frames enabled packet transfers with tcpdump

freebsd# tcpdump -vvn | grep -i 'length 9000'

You should get output like:

16:40:07.432370 IP (tos 0x0, ttl 50, id 63903, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 85825:87285(1460) ack 668 win 14343
16:40:07.432588 IP (tos 0x0, ttl 50, id 63904, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 87285:88745(1460) ack 668 win 14343
16:40:07.433091 IP (tos 0x0, ttl 50, id 63905, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 23153:24613(1460) ack 668 win 14343
16:40:07.568388 IP (tos 0x0, ttl 50, id 63907, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 88745:90205(1460) ack 668 win 14343
16:40:07.568636 IP (tos 0x0, ttl 50, id 63908, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 90205:91665(1460) ack 668 win 14343
16:40:07.569012 IP (tos 0x0, ttl 50, id 63909, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 91665:93125(1460) ack 668 win 14343
16:40:07.569888 IP (tos 0x0, ttl 50, id 63910, offset 0, flags [DF], proto TCP (6), length 9000) 192.168.1.2.80 > 192.168.1.1.60213: . 93125:94585(1460) ack 668 win 14343

b.) Testing if Jumbo Frames are enabled with ping

Testing Jumbo Frames with ping command on Linux

linux:~# ping 192.168.1.1 -M do -s 8972
PING 192.168.1.1 (192.168.1.1) 8972(9000) bytes of data.
9000 bytes from 192.168.1.1: icmp_req=1 ttl=52 time=43.7 ms
9000 bytes from 192.168.1.1: icmp_req=2 ttl=52 time=43.3 ms
9000 bytes from 192.168.1.1: icmp_req=3 ttl=52 time=43.5 ms
9000 bytes from 192.168.1.1: icmp_req=4 ttl=52 time=44.6 ms
--- 192.168.0.1 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3003ms
rtt min/avg/max/mdev = 2.397/2.841/4.066/0.708 ms

If you get insetad an an output like:

From 192.168.1.2 icmp_seq=1 Frag needed and DF set (mtu = 1500)
From 192.168.1.2 icmp_seq=1 Frag needed and DF set (mtu = 1500)
From 192.168.1.2 icmp_seq=1 Frag needed and DF set (mtu = 1500)
From 192.168.1.2 icmp_seq=1 Frag needed and DF set (mtu = 1500)

--- 192.168.1.1 ping statistics ---
0 packets transmitted, 0 received, +4 errors

This means a packets with maximum MTU of 1500 could be transmitted and hence something is not okay with the Jumbo Frames config.
Another helpful command in debugging MTU and showing which host in a hop queue support jumbo frames is Linux's traceroute

To debug a path between host and target, you can use:

linux:~# traceroute --mtu www.google.com
...

If you want to test the Jumbo Frames configuration from a Windows host use ms-windows ping command like so:

C:\>ping 192.168.1.2 -f -l 8972
Pinging 192.168.1.2 with 8972 bytes of data:
Reply from 192.168.1.2: bytes=8972 time=2ms TTL=255
Reply from 192.168.1.2: bytes=8972 time=2ms TTL=255
Reply from 192.168.1.2: bytes=8972 time=2ms TTL=255
Reply from 192.168.1.2: bytes=8972 time=2ms TTL=255
Ping statistics for 192.168.1.2:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 2ms, Maximum = 2ms, Average = 2ms

Here -l 8972 value is actually equal to 9000. 8972 = 9000 – 20 (20 byte IP header) – 8 (ICMP header)

What is the real development costs of Debian GNU / Linux – How much costs the development of a Free Software projects

Friday, February 17th, 2012

Free Software (FS) is free as in freedom as well as free as in price. Free and Open Source Software (FOSS) is developed by geek hobbyist which voluntarily put their time and effort in writting, testing and sharing with anyone for free million of lines of programming code. This doesn't mean however the price of free software costs is 0 (zero). Though the "end product" –  Free Software developed is FREE, "real" software costs as with any other product costs huge money.

I've recently read on Jeb's blog an estimation on how much is the cost of one of the major Free Software project efforts – Debian GNU / Linux
According to James E. Brombergerthe whole Debian project was estimated to be at the shocking price of $19 billion – $19 000, 000, 000 !!!

Here is how JEB got the $19 billions, a quote taken from his blog:

"By using David A Wheeler’s sloccount tool and average wage of a developer of US$72,533 (using median estimates from Salary.com and PayScale.com for 2011) I summed the individual results to find a total of 419,776,604 source lines of code for the ‘pristine’ upstream sources, in 31 programming languages — including 429 lines of Cobol and 1933 lines of Modula3!

In my analysis the projected cost of producing Debian Wheezy in February 2012 is US$19,070,177,727 (AU$17.7B, EUR€14.4B, GBP£12.11B), making each package’s upstream source code worth an average of US$1,112,547.56 (AU$837K) to produce. Impressively, this is all free (of cost).

James has done incredible job with this great research and he deserves applause.
However I believe the numbers proposed by his research are slightly different if we speak about realistic cost of Debian GNU / Linux.
The real costs of the working software ready to install on a user PC are way higher, as according to Jeb's research only the software cost based on code line count is considered.

Hence James software estimation calculates only the programming costs and miss many, many factors that constitute the software end cost.
Some of the many, many REAL COST / expenses for developing a huge Free Software project like Debian GNU / Linux to be considered are:
 

a) bandwidth costs for hosting free software (on the server side)b) bandwidth cost for developers or FS users downloading the software

a) Time spend to spread the word of the great added value of Debian and bundled software (Mouth by Mouth Marketing)

b) Time spend to advertise Debian and its free software components on blogs, social networks (identi.ca, facebook, twitter) etc.(Voluntary online Marketing, SEO etc.)

c) Time spend on generating ideas on future program versions and reporting them to Debian FS community

d) Time on evaluation and feedback on software

e) Time spend on managing free software repository (download) servers voluntarily (by system administrators)

f) Time spend by users on Bug Tracking & Bug Reporting

g) Time spend on research and self-actualization by software developer)

h) Time spend on software Quality Assurance

This are most of the multiple factors which should probably influence the cost of any non-free (proprietary software) project. No matter this costs apply for non-free software, it perfectly applies for free software as well.With all said if if we assume the non-programming costs are equal to the programming costs of $ 19 000 000 000 (suggested by Jeb). This means the real cost of Debian will presumably be at least $32 000 000 000. Putting $ 19 billion for all this long list of "additional" costs (besides pure source) factors is probably still very under-scored number.
 

  • the developers use of their own computers (hardware depreciation)
  • electricity bill of the volunteer (developer) working on the program or project
  • electricity bills for servers where free software is stored and available for download
  • volunteer developer IT skills and tech knowledge (KNOW HOW)
  • Internet, network, dial up bandwidth cost
  • personal time put in FS development (programming, design, creativity etc.)! here the sub costs are long:
  • Costs for Project Management Leaders / Project Coordination
  • The complexity of each of the projects constituting Debian

Very interesting figure from Jeb's research is the Programming Languages break down by source code figure.
Jamesresearch reveals on the 4 major programming languages used in the 17000+ software projects (part of Debian GNU / Linux):

 

  • ANSI C with 168,536,758 – (40% of all projects source code)
  • C++ at 83,187,329 – (20% of all projects source)
  • Java 34,698,990 – (lines of code 8% of sources)
  • Lisp – (7% of all projects source code)

  His research also provides a general idea on how much the source code of some of the major FOSS projects costs. Here is a copy of his figures
 

Individual Projects

Other highlights by project included:

Project Version Thousands
of SLOC
Projected cost
at US$72,533/developer/year
Samba 3.6.1 2,000 US$101 (AU$93M)
Apache 2.2.9 693 US$33.5M (AU$31M)
MySQL 5.5.17 1,200 US$64.2M (AU$59.7M)
Perl 5.14.2 669 US$32.3M (AU$30M)
PHP 5.3.9 693 US$33.5M (AU$31.1M)
Bind 9.7.3 319 US$14.8M (AU$13.8M)
Moodle 1.9.9 396 US$18.6M (AU$17.3M)
Dasher 4.11 109 US$4.8M (AU$4.4M)
DVSwitch 0.8.3.6 6 US$250K (AU$232K)

 

As you can imagine all the source evaluation results, are highly biased and are open for discussion, since evaluating a free software project/s is a hard not to say impossible task. The "open" model of development makes a project very hard to track, open source model implies too many unexpected variables missing from the equation for clear calculation on costs. What is sure however if turned in money it is very expensive to produce.  At present moment Debian Project is sponsored only through donations. The usual yearly budget 5 years ago for Debian  was only $80 000 dollars a year!! You can check Debian Project annual reports throughout the years here , for year 2012 Debian Project budget is as low as $ 222, 677 (US Dollars)! The output price of the software the project provides is enormous high if compared to the low project expenses!

For us the free software users, price is not a concern, Debian is absolutely free both  as in freedom and free as in beer 😉
 

How to add manually adsense code to your wordpress blog in blog index and single page posts

Thursday, April 7th, 2011

I’ve recently realized that the Easy Adsenser plugin which I used to place google adsense advertisements on my blog, is probably stealing some portion of my clicks.

There were some fraud reports on wordpress.org by people who have found out the author of Easy Adsenser rips clicks, by showing sometimes his own ad code even if the plugin is configured to not grant any clicks as a donation to the plugin author.
I don’t know how true this story is and I don’t have the time to observe the whole plugin code to say for sure if the rumors about clicks stealing are true.

However as I’m paying my internet access (that guarantees) by blog to stay online with some adsense advertisements and the adsense revenues are either equal to my internet tax or a bit higher (depending on the month), it’s quite unpleasent to hear someone is stealing from the ads clicks which still generate very low revenue.

Thus I took the time to read some blog posts online which gave me some hints on how can I directly place the google adsense advertisement code into the theme template files

My goal was to place one google adsense ad to appear right after the title of each article and one to appear as a vertical bar in the end of my sidebar.

In this article in short I’ll explain how I achieved this banner placement via the default wordpress template which obviously I use on my blog.

Let’s start:

1. Add adsense to the index page of the blog

Edit your blog/wp-content/themes/default/index.php file

Therein find the code:

<div id="content" class="narrowcolumn" role="main">

and right after this line put the following php code:

<?php
$postnum = 1;
$showadsense1 = 1;
?>

This code is necessery to assure the adsense code only appears on the first blog post from the blog index page

2. Find the code:

<small><?php the_time('F jS, Y') ?> <!-- by

Immediately after the code place the php code:

<?php if ($postnum == $showadsense1) {
echo '<div class="adsense" style="float:right;margin:12px;">;paste here your adsense code ...</div>';
} ?>

<?php $postnum++; ?>

Now with this changes, 1 adsense advertisements should start appearing right after your first and only on your blog post, next step is to place manually one more vertical adsense banner.

2. Place adsense vertical bannre in wordpress blog sidebar

Login with admin user to wordpress and navigate to:

Appearance -> Widgets

Among the available widgets you will notice the widget called Text click over: Add to add this widget to the list of widgets to appear on your blog sidebar.

Afterwards look up over the Sidebar list of widgets find the newly added Text widget and click over Edit to modify it’s content.

Further on put a Title for the widget or choose to leave the title field as blank if you don’t want a name to appear.
On the next textbox just paste your adsense code and you’re done. A simple refresh of your wordpress blog index page should show you a vertical banner with your adsense code.
! Note that if you have recently issued the adsense code it will take about 10-20 minutes until the banner starts showing up.

Until now wordpress is configured to show adsense adverts on the blog main page, as a next step we need to place the same adsense adverts to appear whether a single blog post is reviewed (opened).

Place an adsense advertisements to single posts opened

For that purpose it’s necessery to edit the file single.php it’s again located in blog/wp-content/themes/default

Once again you will first need to find the code:

if (have_posts())

Put the code after the end of the line on a new line:

<?php
// below code is for adsense
$postnum = 1;
$showadsense1 = 1;
?>

Next lookup in the file for the code:

<h2><?php the_title(); ?></h2>

On a new line after it place:

<?php if ($postnum == $showadsense1) { echo '<div class="adsense" style="float:right;margin:12px;"><script type="text/javascript"> place here your adsense code </div>';
} ?>

<?php $postnum++; ?>

That’s all now the adsense advertisements will be also showing on the single blog posts reviews found via some search engine (google, yahoo etc.).

Hope this article will be helpful to somebody, if so drop me a thanks line in comments 😉

How to add multi language support to wordpress with qTranslate

Monday, October 3rd, 2011

QTRanslate WordPress Language Translate Screenshot 1

Lately, I have to deal with some wordpress based installs in big part of my working time. One of the wordpress sites needed to have added a multi language support.

My first research in Google pointed me to WPML Multilingual CMS The WordPress Multilingual Plugin
WPML Multilingual CMS looks nice and easy to use but unfortunately its paid, the company couldn’t afford to pay for the plugin so I looked forward online for a free alternative and stumbled upon QTranslate

QTranslate is free and very easy to install. Its installed the wordpress classic way and the installation went smoothly, e.g.:

1. Download and unzip QTranslate

# cd /var/www/blog/wp-content/plugins
/var/www/blog/wp-content/plugins# wget http://downloads.wordpress.org/plugin/qtranslate.2.5.24.zip
...
/var/www/blog/wp-content/plugins# unzip qtranslate.2.5.24.zip
...

Just for fun and in case the plugin disappears in future, a mirror of Qtranslate 2.5.24 is found here

2. Enable QTranslate from wordpress admin

Plugins -> Inactive -> qTranslate (Activate)

After activating the plugin, there is a Settings button from which qTranslate‘s various plugin parameteres can be tuned.

qTranslate WordPress translate screenshot 2

In my case my site had to support both English and Arabic, so from the settings I added support for Arabic translation to the wordpress install.

Adding Arabic is done in the following way:

a. From the Language Management (qTranslate Configuration) from the Languages menu and the Languages (Add Languages) I had to choose a language code (in my case a language code of ar – for Arabic). Next I had to choose the Arabic flag from the follow up flag list.

In next text box Name , again I had to fill Arabic, for Locale en_US.UTF-8
The following Date Format and Time Format text boxes are optional so I left them blank.
To complete the process of adding the Arabic as a new language wordpress should support I pressed the Add Language button and the Arabic got added as a second language.

Afterwards the Arabic was added as second language, on the bottom of the left wordpress menu pane a button allowing a switch between English, Arabic appeared (see below screenshot):

MultiLingual WordPress with qTranslate

Finally to make Arabic appear as a second language of choice on the website I added it as a Widget in the Widgets menu from the AWidgets menu:

Appearance -> Widgets

In widgets I added qTranslate Language Chooser to the Sidebar without putting any kind of Title for qtranslate widget .
I found it most helpful to choose the Text and Image as an option on how to display the Language switching in the wp.

How to compile latest qmailadmin (qmailadmin 1.2.15) on Debian Squeeze Linux

Thursday, August 11th, 2011

I’ve completed a qmail installation few days ago on a fresh installed Debian Squeeze 64 bit server. All is configured and works fine, except qmailadmin and vqadmin.
As the mail server was missing any kind of web mail administration panel, I needed to make at least one of the two above to make with qmail.

I decided to concentrate on qmailadmin and took the time to make it work. I used the following command lines and got the compile failure during make compilation:

debian:/usr/local/src/qmailadmin-1.2.15# ./configure --enable-cgibindir=/usr/lib/cgi-bin --enable-htmldir=/var/www/qmailadmin/ --enable-modify-quota
...
debian:/usr/local/src/qmailadmin-1.2.15# make
...

The source make failed with the following error:

In file included from template.c:45:
qmailadmin.h:37:1: warning: "MAX_FILE_NAME" redefined
In file included from template.c:28:
/home/vpopmail/include/vpopmail.h:146:1: warning: this is the location of the previous definition
template.c: In function "send_template_now":
template.c:505: error: "VERSION" undeclared (first use in this function)
template.c:505: error: (Each undeclared identifier is reported only once
template.c:505: error: for each function it appears in.)
make[1]: *** [template.o] Error 1
make[1]: Leaving directory `/usr/local/src/qmailadmin-1.2.15'
make: *** [all] Error 2

To workaround these compile issues, I’ve had to modify the C source file belonging to qmailadmin ( template.c ), e.g.:

debian:/usr/local/src/qmailadmin-1.2.15# vim template.c

In the file I had to add besides the line:

#include "util.h"

The code:

#define VERSION ""

Aterwards qmailadmin’s compile and install via make && make install-strip succeeded and now works perfectly fine 😉

How to print simple text pages on Linux in console with old LPR parallel port attached printer

Tuesday, February 7th, 2012

LPT parallel port pinout diagram with explanations

Many younger people, might not know lpr command, historically it was heavily used for printing in the early GNU / Linux days.
lpr ships the text to be printed to the printer which is physically attached on LPT (Line Print Terminal) parallel port . Those who lived the DOS era surely know in those "ancient" days, everyone who wanted to print has to use the LPT parallel port

Present time, everyone knows there is almost no modern printer that is attached to the PC via LPT port but rather the USB port is used for communication between the printer the computer.
Nevertheless The USB printers on Linux are managed by CUPS, the lpr command is still functional shipping the text to be printed via CUPS (cups-lpd daemon).
Before cups-lpd was introduced the service managing the print jobs was lpd
Hence lpr is still functional.

To print a plain text file of one page with lpr on Linux:

linux:~# cat text-file-to-print.txt | lpr

For multiple printers to switch between multiple printers there is the PRINTER shell variable:

linux:~# export PRINTER=printer-Name-and-Type

To print a really long text file (a book in TXT) the pr command comes handy. As you can read in the cmd manual pr converts text files for printing

Lets say you would like to have a 60 lines of text per printed page, the cmd to issue is:

linux:~# pr -l60 text-file-to-print.txt | lrp

All queued printing jobs can be reviewed with the lpq, if you have a printer attached try:

linux:~# lpq
lp is ready and printing
Rank Owner Job Files Total Size
active hipo 1 text-file-to-print.txt 62045 bytes

Since some years it is pretty rare for people to use lpq, since most of the parallel printing is managed by CUPS server, what most people use nowdays to check the printer queue is lpstat : e.g.

linux:~# lpstat
...

Printing status and all things related to queued jobs for printing gets logged in /var/log/lpr.log

There is even more simplistic way to print directly to the printer (if the printer is attached via a LPT port) through the kernel /dev/lp, for example:

linux:~# cat text-file-to-print.txt >> /dev/lp

For more than one printer attached the naming of /dev/lp, might probably be /dev/lp0, /dev/lp1 etc.
The lprm command also exists in case if you would like to cancel a printjob in the queue. Lets say I want to cancel a job in the queue with Job ID 5:

linux:~# lrpm 5
...

To cancel a current running job in the middle the /usr/bin/cancel command exists.

An interesting historic fact is that nowdays opening lpr, lpq or any of the other tools for simple text mode printing one sees on top of the page Apple Inc.

Lets clear this up CUPS (Common Unix Printing System) (open source) printing platform is not owned by Apple, since it is licensed under GPL2 and LGPL. The reason why the Apple Inc. shows up in man pages is because in year 2007, the founder of CUPS printing server Michael Sweet hired him to work for Apple Inc. "purchasing" the CUPS source. However as we know they did not really purchased the code, because the code was already belonging to the community (licensed under GPL2). Apple however as a marketing trick used the fact that Sweet worked for them and as probably as a matter of marketing asked him to place the Apple Inc. in the copyright source and manual areas. Obviously this is not true, since Apple Inc. does not hold copyright for CUPS as CUPS can be copied by anyone (its open source) 😉

Most of the people will never print using this commands, since printing is now, ages ahead, anyways for simple people (like me), who just need to print a text with no special fonts or graphics text printing is just great.

Text printing is also a good learning experience for Linux novices and is good to be known just as a piece of UNIX history.

Kill everything that Moves (KETM) an arcade spaceship Tyrian GNU / Linux game

Saturday, January 7th, 2012

I always love so much to go back to the times, when games were games and people had still valued words like moral and respect.
In that great days of old school computing, we used to play the awesome old schools Tyrian and the Nintendo 1941 game (hopefully some still remember).

KETM Tyrian like Old School 2d Spaceship shooter awesome

For all who don't Tyrian is one of the best Spaceship Arcades of all times!, and especially for DOS operating system the best I've personally seen.

Recently I was checking the arcade games available for install on my Debian GNU / Linux and happily come across a game called KETM.

KETM acronym stands for the memorizable KILL EVERYTHING THAT MOVES and is free software distributed game under GPL.
The original creation idea was probably to resemble the so famous in the '90s spaceshooter games.

KETM is pretty addictive just like tyrian and has santimental meaning for me since it brings me memories for my arcade gaming years 😉

The game is easy to play and has a feeling of "diversity" especially in type of weapons your ship can obtain and use against enemies.

The powerups you get is quite plenty compared to the enemy ship types you should destroy 😉 In overall the game is quite easy to play, this however is also a good thing, as you can play more smoothly without dying every few secs like it is in so many arcade games…

The game has only 4 game levels and on each level end there is a big spaceship "the boss" which is the last in line to destroy in the tradition of the 2d arcade games.

KETM Tyrian like Linux Debian arcade game

Kill Everything That Moves is available for Debian and Ubuntu as a deb installable with apt. To install the game on Debian and Ubuntu

debian:~# apt-get install ketm
...

ketm's official latest available source and binary of time of writting this article is at version 0.6 and as far as I checked it unfortunately seems like the game development is stucked and the code seems a unmaintained.
I'm sure ketm has a lot of potential en hope somebody will adopt the code and will push further its development.
The game runs by default in the annoying windowed mode, I don't like this so I always run it fullscreen:

Kill Everything that Moves Tyrian like arcade game for Debian Ubuntu Linux

debian:~# ketm -f

KETM also reminds a bit on GEKI 2 / 3, which I have previously blogged about but I found KETM to be more enjoyable than gekis.
I've seen KETM has RPM ports as well so installing the game on fedora will be probably as easy as downloading the respective RPMs fulfilling the RPM package requirements and installing with rpm -i. I would be glad to hear from people who had succesfully run the game on Fedora and other RPM based Linux distributions?

The only thing that prevents the game to feel a bit more awesome (in my view) is the missing sound & music … Even though in the game settings inside the main menu there is an option for Sound On / Off the game runs by default without any sound or music (at least on my Debian).
I hope you will have some fun with KETM just I like I did! 😉
Also if you haven't played Tyrian yet, then I strongly advice you download Tyrian from here and try it out with dosbox (a dos gnu linux / bsd game emulator)

Absolute Game Classics Tyrian native game play with dosbox Linux screenshot

Interesting fact to mention here,  while looking for the native tyrian game info , I found tyrian has an open source version under development called OpenTyrian . I'll check the game and write on it when I have time.