Oliver Huynh's Repository

Linux Log files and usage

=> /var/log/messages : General log messages

=> /var/log/boot : System boot log

=> /var/log/debug : Debugging log messages

=> /var/log/auth.log : User login and authentication logs

=> /var/log/daemon.log : Running services such as squid, ntpd and others log message to this file

=> /var/log/dmesg : Linux kernel ring buffer log

=> /var/log/dpkg.log : All binary package log includes package installation and other information

=> /var/log/faillog : User failed login log file

=> /var/log/kern.log : Kernel log file

=> /var/log/lpr.log : Printer log file

=> /var/log/mail.* : All mail server message log files

=> /var/log/mysql.* : MySQL server log file

=> /var/log/user.log : All userlevel logs

=> /var/log/xorg.0.log : X.org log file

=> /var/log/apache2/* : Apache web server log files directory

=> /var/log/lighttpd/* : Lighttpd web server log files directory

=> /var/log/fsck/* : fsck command log

=> /var/log/apport.log : Application crash report / log file

To view log files at shell prompt

Use tail, more, less and grep command.
tail -f /var/log/apport.log
more /var/log/xorg.0.log
cat /var/log/mysql.err
less /var/log/messages
grep -i fail /var/log/boot

View log files using GUI tools using the GNOME System Log Viewer

System Log Viewer is a graphical, menu-driven viewer that you can use to view and monitor your system logs. System Log Viewer comes with a few functions that can help you manage your logs, including a calendar, log monitor and log statistics display. System Log Viewer is useful if you are new to system administration because it provides an easier, more user-friendly display of your logs than a text display of the log file. It is also useful for more experienced administrators, as it contains a calendar to help you locate trends and track problems, as well as a monitor to enable you to continuously monitor crucial logs.

You can start System Log Viewer in the following ways:

Click on System menu > Choose Administration > System Log:

(The GNOME System Log Viewer)

Note you can start the GNOME System Log Viewer from a shell prompt, by entering the following command:
$ gnome-system-log &

View log files in Ubuntu Linux

- Install mdadm easy by

apt-get install mdadm

- Change a disk to md format:

fdisk /dev/sdd
press "n" to create
press "t" to change format, choose "fd"

- Create a new synching disks. Paired:

mdadm --create --verbose /dev/md3 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdd1

shutdown –r now

- Check all md devices:

cat /proc/mdstat

- Format

mkfs -t reiserfs /dev/md3

- View md device detail :

mdadm --detail /dev/md3

- Add device

mdadm --manage --add /dev/md3 /dev/sdd1

- Check disk's status

fdisk -l | more

Ready to go? Let’s do it!!!

Oliver

Today (November 15) from 9AM(GMT+7) till this time, Drupal is still down. I’m so worried. I guess this is an DDOS attack.

What's Microblog-purple?

The project aims is to develop a set of microblog support in LibPurple base client like Pidgin. Currently it only support Twitter through the conversation windows.

Currently the source can be built and run on Windows Vista and Ubuntu 8.04.1. Other platform with LibPurple should works, but we don't have time (yet) to test it.

Guide:

Ok, if we want change the message in both facebook, and pidgin, just add an account Twitter in Pidgin, and send message "This is message in TWITTER" to user twitter.com in user list(This user will appear when connected).

Microblog-purple is now version 0.1.2

Download from

http://code.google.com/p/microblog-purple/downloads/list

By Oliver

Well, when you trying to restart the mysql in Ubuntu:

/etc/init.d/mysql restart

... [fail] ...

First, you find the error log path of Mysql.

/var/log/mysql.*

But, the final way to fix the MySQL error:

0. su -

1. # backup database files

cp -r /var/lib/mysql /var/lib/mysql.b

2. # remove app

aptitude purge mysql-server

3. # if you have another app:mysql-server-5.0

aptitude purge mysql-server-5.0

4. # reinstall

aptitude install mysql-server

5. # recopy files

cp -r /var/lib/mysql.b /var/lib/mysql

6. # restart mysql

/etc/init.d/mysql restart

You will see, it is faster than your fixing job.

*: If you get error when you remove, check the article "dpkg broken" in this blog.

Regards,

Oliver