Sunday, January 31, 2010

Installing dimdim 4.5 on Centos 5.4 x86_64

Dimdim is a web meeting software. From "Dimdim lets anyone deliver synchronized live presentations, whiteboards and web pages and share their voice and video over the Internet - with no download required".

There are few versions of dimdim, and the one we are going to install is the open source edition.
The steps are:

1. Download dimdim rpm from here
You have to provide email
, first name and last name before you can download.
2. Once downloaded, unzip the file ( and you can find one dimdim rpm file for Centos 5.2, one readme file, one web meeting user guide and one web meeting server integration guide.
# unzip
3. Follow the installation guide in the Dimdim_SF_CentOS5.2_RPM_Readme_v4.5.txt file. After finish with all the pre-requisite check, proceed to installation process.
4. If you have error stating that you have failure in OS check, change your /etc/issue from 5.4 to 5.2
# sed -i 's/5.4/5.2/' /etc/issue
5. If you got an error in missing libpcre, install pcre
# yum install pcre
6. Once installed, open your browser and point your browser to http://localhost/dimdim
7. Start meeting using your newly installed dimdim :)

Monday, January 11, 2010

Setting virtual ip in centos

Virtual ip is an ip that bind to a physical ethernet card that already have physical ip address. To set virtual ip in centos, follow the below steps:

1. We will add virtual ip to eth0. Below is original configuration of /etc/sysconfig/network-scripts/ifcfg-eth0. ifcfg-eth0 is the original configuration file for eth0.
# vi /etc/sysconfig/network-scripts/ifcfg-eth0


2. Create new virtual configuration file by copying and editing(change IPADDR and remove HWADDR) the ifcfg-eth0 configuration file

# cd /etc/sysconfig/network-scripts
# cp ifcfg-eth0 ifcfg-eth0:0
# vi ifcfg-eth0:0


3. Restart network
# /etc/init.d/network restart

4. Check your new virtual ip using ifconfig
# ifconfig

Thursday, January 7, 2010

Using alias in bash

Alias is some kind of shortcut in command lines, and it can be really productive if you can alias all the long commands that you use to manage your linux system.


To permanently set alias "d=dmesg | tail" for user "abu"

1. Append "alias d=dmesg | tail" to the /home/abu/.bashrc
$ echo "alias 'd=/bin/dmesg | /usr/bin/tail'" >> /home/abu/.bashrc

2. Activate the change
$ . /home/abu/.bashrc

3. Test the new alias
$ d
[drm] LVDS-8: set mode 16
[drm] LVDS-8: set mode 17
[drm] LVDS-8: set mode 18
[drm] LVDS-8: set mode 19
[drm] LVDS-8: set mode 1b
[drm] LVDS-8: set mode 1d
[drm] LVDS-8: set mode 1e
[drm] LVDS-8: set mode 1f
[drm] LVDS-8: set mode 20
[drm] LVDS-8: set mode 21

To temporarily set alias, just use the alias command at the terminal

$ alias d='dmesg | tail'

To remove alias. you can either delete it from ~/.bashrc or use unalias command

$ unalias d

Tuesday, January 5, 2010

Continue stalled scp file transfer session

Stalled scp file transfer session will happen when the network connection is unstable. You can see the status of the session at the message shown at your stdout like below:

file1 3% 136MB 0.0KB/s - stalled -

To continue back the file transfer, you can use this command at a new terminal, but make sure both the server and client have rsync installed:

$ rsync --partial --progress --rsh=ssh username@server:/path/to/remote-file /path/to/local-file

For example, if the transfer of file1 is stalled for user abu:

$ rsync --partial --progress --rsh=ssh abu@master:/home/abu/file1 /home/abu/file1

The scp transfer process will continue transferring the file

file1 4% 136MB 300.0KB/s 2:03:17 ETA