Num key restarts/kills Gnome session

If you have upgraded to Ubuntu 8.04, and are facing this annoying issue where you press a num key and it restarts/kills your gnome session - you will have to do the following steps to get rid of the issue

In Gnome Menu -

1) System
2) Preferences
3) Keyboard (Tab: Mouse Keys)
4) Uncheck (Allow to control pointer using the keyboard).

Via Ubuntu Bugs

Advanced Glow Effects in Photoshop

Here is a tutorial to create some really sharp looking glow effects using a combination of layer styles, the pen tool and colour blending.

The end effect is quite amazing as you look in the picture above (click on the image)

See the tutorial here

Gmail features you may not know

Gmail has a lot of features :-) .. The gmail team has put up a list of features that are very useful once you know them ..

Here are the list of gmail features


1. Create event

2. Offline chat

3. Advanced search

4. Conversation update notification

5. Smart links on the right

6. Gmail for mobile application

7. Reply by chat

8. Gmail gadget for iGoogle

9. Open attachments in Google Docs & Spreadsheets, or view as slideshow

10. Custom "from"

Reboot your Frozen Linux based system

Ctrl-Alt-Backspace doesn't work ?

Try this

Hold down the Alt and SysRq (Print Screen) keys.

While holding those down, type the following in order. Nothing will appear to happen until the last letter is pressed: REISUB

Watch your computer reboot magically.

What the individual keys do in that sequence are not as important as what it does as a whole: stops all programs, unmounts all drives, and reboots.

To remember this,

Raising Skinny Elephants Is Utterly Boring or R E I S U B - is just the word busier in reverse.

R gives back control of the keyboard
S issues a sync
E sends all processes but init the term singal
I sends all processes but init the kill signal
U mounts all filesystem ro to prevent a fsck at reboot
B reboots the system

Via Fosswire

Gmail Search Power Tips!

Search on your Gmail like a pro with these power tips! Ofcourse you could use the search options to do these, but learning the "keyword" options is plain faster and little more powerful especially when you want to find mails between particular dates.

There are few keywords that you can use in the search box you see above (appears when you load Gmail)

from:
to:
subject:
label:
after:
before:
in:
is:
has:

For the above, you could provide the following options as below

from:

from: {email address}
from: {name}

to:

to : {email address}
to : {name}

subject:

subject: {subject}

after:

after: {date in any known format} - For example : March 25, 10/10/2006, etc

before:

before: {date in any known format} - For example : March 25, 10/10/2006, etc

in:

in: inbox (Searches Inbox)
in: chat (Searches Chat)
in: drafts (Searches Drafts)
in: spam (Searches spam)
in: trash (Searches Trash)
in: anywhere (Searches All the Mail including Trash & Spam)


is:

is: starred (Searches Starred Mail)
is: sent (Searches Sent Mail)
is:read (Searches Read Mail)
is:unread (Searches Unread Mail)

has:

has:attachment (Checks for mail with Attachment)

label:

label: {label_name} (Checks in mail with Label name)

Other general options include

{search_keyword} and - {search_keyword} which means search for {search_keyword} or doesn't have {search_keyword} in your mail


Example:

Find all mail which was addressed to techflock before 19th Dec 2006 and After 1st November 2006 and has networking but not basic in the mail with IMP as label

Your search query would be

before:2006/12/19 after:2006/11/01 to:techflock label:IMP in:anywhere networking -basic

I use these filters to re-label (or delete) old mails. You could create Filters too... however, Google doesn't have the option to use before: after: keywords in your filter.

Checking for rootkits

The term "rootkit" (also written as "root kit") originally referred to a set of recompiled Unix tools such as "ps", "netstat", "w" and "passwd" that would carefully hide any trace of the intruder that those commands would normally display, thus allowing the intruders to maintain "root" on the system without the system administrator even seeing them.

Generally now the term is not restricted to Unix-based operating systems, as tools that perform a similar set of tasks now exist for non-Unix operating systems such as Microsoft Windows, regardless of the existence (or lack of existence) of a "root" in the operating system. (Wikipedia.org)

In Linux, you can check for rootkits using 2 different programs

1. chkrootkit
2. rkhunter

chrootkit

One of the popular rootkit checking programs, this program can check for any
rootkits installed on your local machine

On Ubuntu/Debian

sudo apt-get install chkrootkit

Download from http://www.chkrootkit.org/download/

rkhunter

rkhunter does what chkrootkit does plus a whole lot more.

rkhunter can also be updated with the latest definitions and can be run
through cron as well.

On Ubuntu/Debian

sudo apt-get install rkhunter

Download from http://rkhunter.sourceforge.net/

Apache Performance Tips - Part 1

A few basic tips will go a long way in enhancing your Apache performance. You will have to put in the directives in your httpd.conf or the through a seperate .conf file which you can include through the httpd.conf file.

1. Cache those frequent pages!

How often do you see the Home Page being very slow to load up? A tip would be to use a caching module to cache those pages you think will be loaded very frequently. These pages will be loaded in the memory instead of being retrieved from the filesystem everytime.

Module to use:

mod_file_cache

How and What to use:

There are 2 directives that you can use MMapFile and CacheFile which you can use to Cache the pages you want.

Read the differences between MMapfile and CacheFile

For Example:

CacheFile /home/web2/index.htm
CacheFile /home/web2/about.htm

The above two directives will cache index.htm and about.htm

Don't forget to read the above module page to find out how to cache the contents of a entire directory ;-)

2. Don't use DNS lookups

You don't use the HostNameLookups directive to lookup for dns names in your log file - This is disabled by default in Apache 1.3 and above versions.

Also, make sure you always use a IP address instead of a domain names in your Allow or Deny directives either. It will cost you a lot of performance.

If you need hostnames in your logfile, you just use logresolve

How to use:

HostNameLookUps Off

3. Keep your site alive

HTTP works by requesting for a document over a new connection. So, everytime you request a document, a new socket connection is established, once served, the connection is closed. The time spent for establishing a connection and closing it can be avoided using a directive called KeepAlive

How to use:

KeepAlive On

Other Related Directives

With the above KeepAlive directive, there are 2 other related directives - MaxKeepAliveRequests and KeepAliveTimeout.

MaxKeepAliveRequests is the number of requests to be allowed over a single connection. Default value for MaxKeepAliveRequests is 100. If you have a lot of memory to spare, you could consider putting MaxKeepAliveRequests to 0 to allow unlimited number of connections

KeepAliveTimeout is used to timeout the connection - you don't want to keep the connection established with the client even though they are not using your site - do you ? 15-20 seconds should be a ideal value for KeepAliveTimeout

How to use:

MaxKeepAliveRequests 100
KeepAliveTimeout 20

4. Consider mod_perl

If you are using CGI perl based web application, it pays to consider to using mod_perl

Read this excellent article on mod_perl

How to do it:

PerlModule ModPerl::PerlRun Alias /cgi-bin/ /opt/apache2/cgi-bin/
<location >
SetHandler perl-script
PerlResponseHandler ModPerl::PerlRun
Options +ExecCGI
< /location >

or

PerlModule ModPerl::Registry
Alias /cgi-bin/ /opt/apache2/cgi-bin/
<location >
SetHandler perl-script
PerlResponseHandler ModPerl::Registry
Options +ExecCGI
< /location >
As you see, there are 2 ways to go about using mod_perl, one is the PerlRun method and other is the Registry method basic difference being that in Registry method, code is cached after compilation whereas it isn't . Read more about the porting guidelines

5. Share the load

If you have 2 or more webservers - you can share the load amongst them by shifting some of the pages to the other webserver.

Module to use:

mod_proxy

How and What to use:

ProxyPass /images/ http://web2.techflock.com/
ProxyPassReverse /images/ http://web2.techflock.com/

Read about the above directives at Apache documentation

...to be continued ..

Meanwhile you can also go through Apache Tuning

Mask your Site

We present to you a few feature as well as security enhancements to mask your webserver and site from web attacks!

• Do not use a default extension even though you use a language like php or aspx. If you can make it go away in entirety - the better! And do use Clean URLs Search engines love Clean URLs
• Modify your header information so that it returns something not so obvious. Take a look at mod_headers module
• Do not use CGI or SSI (Server Side Includes) - both of them are heavy on the server and vulnerable to attacks
• If you have a popular site, you might want to consider using something like Modsecurity which is a web application firewall which allows real time monitoring and analysis
• Get a book - Apache Security is a good start
  

Turn off the annoying system beep

Yes, this is much easier than this

rmmod pcspkr

To Get it back on - woudn't know why you would want to do that !

modprobe pcspkr

Turn off that cranky beep

Ubuntu sounds that cranky bell everytime you enter a command through the virtual console.

Turn it off by issuing the following command!

setterm -blength 0

Gartoon Icons

Really like the Gartoon icons - although they were designed for kids - they do make my Gnome look very silly and nice :). I discovered them when I was fiddling around with Edubuntu

Do check the other icons by Zeus Box Studio

the LANG variable woes

I don't know whether I am going to make any sense of this nor I know why this fixes the problems I face but here you go anyway!

My installation of Linux comes with a LANG variable set to en_US.UTF-8. This however causes my man pages to display some weird characters such as 80x22 for ' (?)

My primary language of communication would be en_US and the way to fix the above weird characters was to unset the LANG variable to nothing

so, I do a export LANG=

and set it to null

Workrave - prevention and recovery of RSI

Workrave is a program available both on Linux & Windows which helps you prevent and recover from RSI (Repetitive Stress Injury). It's a neat piece of software which includes illustrations of the exercises that you can do during your breaks. Have a look at the feature list

Ubuntu users:

sudo apt-get install workrave

Others:

Get it here

CSS Tab Designer - for those sweet menus!

CSS Tab Designer is a tool lets you design those gorgeous CSS based menus like the ones above.

It's free - Get it - Highly Recommended! Works only on Windows based systems

Putting favicon on your Apache

Put a favicon.ico (icon file) into the desired directory /images/favicon.ico under ServerRoot

AddType image/x-icon .ico
<Files favicon.ico>
ErrorDocument 404 /images/favicon.ico
</Files>

favicon should be 16x16 image

AOL IMAP access instructions

This page lets you configure your client to use AOL's IMAP servers. Works both with AOL eAddress and normal AOL email addresses

Desktop Recording on Ubuntu

You want to do a video tutorial for and on Linux?

Install this utility called Istanbul

On Ubuntu:

sudo apt-get install instanbul

Crashed quite frequently for me though. Recording is on ogg format.

Linux Documentation on your Ubuntu

Want to read more about how things work on Linux ?

Install these two packages on Ubuntu and you pretty much have almost all the HOWTO documentation out there!

HOWTO & FAQ

sudo apt-get install doc-linux-html

Non-Free HOWTOs

sudo apt-get install doc-linux-nonfree-html

IBM Shortcuts - Podcasts to increase your productivity

IBM has a weekly show in the form of a podcast to increase your digital productivity

Its called Shortcuts - Go there

Apache Tip - cgi-bin for every user

You want to give cgi-bin access to all the users on your webserver.

Add the following directive entries in your httpd conf file


<Directory /home/*/public_html/cgi-bin/>
Options ExecCGI
SetHandler cgi-script
</Directory>