Add new rule to SpamAssassin

Add this lines to /etc/mail/spamassassin/local.cf:

body LOCAL_DEMONSTRATION_RULE   /test/
score LOCAL_DEMONSTRATION_RULE 0.1
describe LOCAL_DEMONSTRATION_RULE       This is a simple test rule

then you must restart the SpamAssassin Process:

/etc/init.d/psa-spamassassin restart

You can also add rule to each user in ~/.spamassassin/user_prefs

but remember that by default allow_user_rules is 0, and you must change
that to 1. Add this line to:

/etc/mail/spamassassin/local.cf


allow_user_rules 1

Don't forget to restart the SpamAssassin.

Migrate MySQL to Oracle

http://www.oracle.com/technetwork/database/migration/mysqllauncher-086083.html

Likewise-Open: Authenticate a Linux machine to an Active Directory domain

To install the likewise-open package in Ubuntu, open a terminal prompt and enter:

sudo apt-get install likewise-open

Or you could download appropriate Script from here.

The main executable file of the likewise-open package is /usr/bin/domainjoin-cli, which is used to join your computer to the domain. Before you join a domain you will need to make sure you have:

• Access to an Active Directory user with appropriate rights to join the domain.

• The Fully Qualified Domain Name (FQDN) of the domain you want to join. If your AD domain does not match a valid domain such as example.com, it is likely that it has the form of domainname.local.

• DNS for the domain setup properly. In a production AD environment this should be the case. Proper Microsoft DNS is needed so that client workstations can determine the Active Directory domain is available.

  
  

To join a domain, from a terminal prompt enter:

sudo domainjoin-cli join example.com Administrator

See here for more details.

Qmail & SpamAssassin - Change Default Rules Score

Under this directory:

/var/qmail/mailnames/DOMAIN-NAME/USERNAME/.spamassassin

edit user_prefs and add the new Score for desire rule:

Example:

score RDNS_NONE 5.0

that overrides the defualt score.

You can find all rules here:

http://wiki.apache.org/spamassassin/Rules/

Ubuntu - Convert jpg files to gif animator

Run this command:

convert -delay 10 -loop 0 *.jpg animation.gif

Chrooted SSH/SFTP

with these settings, works for me in Debian Lenny:

Be sure that this line in /etc/ssh/sshd_config exists:

Subsystem sftp internal-sftp

Chroot the user to his home:

ChrootDirectory %h

The owner of home must be root (mod 755).

These lines are important, otherwise the root user could not login into system:

Match User root
ChrootDirectory /

Restart the ssh process:

/etc/init.d/ssh restart

Colored output in bash

Use escape sequences:

echo -e '\E[color1;color2mYour Text.'
(color1 is the foreground, color2 the background color)

Shell Scripting Syntax

 echo -e '\E[30m black \E[31mred \E[32mgreen \E[33myellow \E[34mblue \E[35mmagenta \E[36mcyan \E[37mwhite'
 echo -e '\E[30;41mblack on red'

<strong class="highlight">echo</strong> -e '\E[30m black \E[31mred \E[32mgreen \E[33myellow \E[34mblue \E[35mmagenta \E[36mcyan \E[37mwhite' <strong class="highlight">echo</strong> -e '\E[30;41mblack on red'

Shell Scripting Syntax

Color:           Foreground:           Background:
---------------------------------------------------------
black             30                       40
red               31                       41
green             32                       42
yellow            33                       43
blue              34                       44
magenta           35                       45
cyan              36                       46
white             37                       47

Counting files number in a directory under Linux

One way is:

ls -1 /YOUR/DIRECTORY | grep -c ""

Ubuntu - If your desktop icons are disappeared, try this

Press Alt+F2 and type gconf-editor in window.

Then apps --> nautilus --> preferences

Make sure "show_desktop" is checked.

If it's checked then double click on it and hit ok.

Send test mail from command line with Sendmail

In shell run this command:

( echo subject: test; echo ) | sendmail -v -oi YOUR-EMAIL@ADDRESS.COM

MySQL - debian-sys-maint account

Find your debian-sys-maint password in /etc/mysql/debian.cnf.

Then use this command in Mysql shell:

GRANT ALL PRIVILEGES ON *.* TO 'debian-sys-maint'@'localhost' \
IDENTIFIED BY 'PASSWORD' WITH GRANT OPTION;

Replace PASSWORD with your debian-sys-maint password.

Backup and restore debian/ubuntu package selection

If you are running Debian and have lost track of which packages you are running, it could be useful to get a backup of your currently installed packages. You can get a list by running:

dpkg --get-selections > debianlist.txt

This will put the entire list in debianlist.txt. You could then install the same packages on a different computer with:

dpkg --set-selections < debianlist.txt

You should bear in mind that you would also need to copy over configuration files from /etc when copying your system to a new computer.

To actually install the selections, use:

apt-get -u dselect-upgrade

Source: http://www.tuxradar.com/content/linux-tips-every-geek-should-know

Convert a ssh-keygen to putty format using puttygen

First install putty-tools:

apt-get install putty-tools


then use this command to convert ssh-key:

puttygen YOUR-KEY -o OUTPUTFILE.PPK

How-To: Find missing packages in Debian

apt-file is a command line tool for searching packages in Debian/Ubuntu repositories.
Unlike apt-cache search, apt-file can find files in uninstalled or can list the content of uninstalled packages.

First, we will install the apt-file package:

apt-get install apt-file

then we need to update database:

apt-file update

now we can query the database for myfile:

apt-file search FILENAME