try this
yum clean all yum makecache yum update
Error Message: Metadata file does not match checksum [Centos 5 yum ]
July 26th, 2010screen :- tool for sysadmin
July 25th, 2010When you have to do ssh and work, try to give “screen” command . It will save you
Some screen commands to remember
- screen -ls will list the current screen sessions running on a machine.
- Control+a (press Control and then press a) Will toggle between your current shell and your previous shell
- Control+a d will detach you from a session.
Basics of how to use screen on a Linux/Ubuntu machine
Create a session :-
screen -S sessionname
Here I am giving “screen -S nuxeo” //I am working on nuxeo , so I named it
We can have up to 10 interactive shells open in one window.When we start a new session we are in shell 0.
To create more shells,Press cntrl key, then press and release the “a” key and type letter “c”
switching between shells
press ctrl, then press and relase “a” key and then press the shell no
GNU Screen allows you to manage several interactive shell instances within the same “window.” By using different keyboard shortcuts, you are able to shuffle through the shell instances, access any of them directly, create new ones, kill old ones, attach and detach existing ones.
Instead of opening up several terminal instances on your desktop or using those ugly GNOME/KDE-based tabs, Screen can do it better and simpler.
Not only that, with GNU Screen, you can share sessions with others and detach/attach terminal sessions. It is a great tool for people who have to share working environments between work and home.
remote desktop on CentOS
July 25th, 2010check the service vncserver is running
if running
give vncserver :desktopno
ie vncserver: 1
now you will be able to use ur client remote desktop to connect to the centos
running DM nuxeo with JBOSS
July 25th, 2010My DM nuxeo on Jboss was not able to access from the LAN
It was because by default JBossAS binds its services to localhost (127.0.0.1) *by default*, instead of binding to all available interfaces (0.0.0.0). This was primarily done for security reasons because of concerns of users going to production without having secured their servers properly.
We can enable it by running “/opt/nuxeo-dm/bin/run.sh -b 0.0.0.0 “
finding PCI devices
July 22nd, 2010Some times you need to find out the device name and other details . U can use the command
lspci = Which list all PCI devices
lshw = List hardware
lshw -C network = List device which are under group network
To find PCI devices , let us say network
lspci -v | grep Ethernet -A 1
18:00.0 Ethernet controller: Broadcom Corporation NetLink BCM5787M Gigabit Ethernet PCI Express (rev 02)
Subsystem: Hewlett-Packard Company Device 30c0
##
To find the info about network devices
it is “ifconfig”
Finding the size of a directory
July 12th, 2010$du
Typing the above at the prompt gives you a list of directories that exist in the current directory along with their sizes. The last line of the output gives you the total size of the current directory including its subdirectories. The size given includes the sizes of the files and the directories that exist in the current directory as well as all of its subdirectories. Note that by default the sizes given are in kilobytes.
$du -ch | grep total
This would have only one line in its output that displays the total size of the current directory including all the subdirectories.
$du –exculde=doc
The above command would display the size of the current directory along with all its subdirectories, but it would exclude all the files having the given pattern present in their filenames. Thus in the above case if there happens to be any doc files within the current directory or any of its subdirectories, their size would not be included while calculating the total directory size.
$du -ch | sort -rn
Listing the disk space used for a directory and its subdirectories, sorted by disk usage
It is only for ………………………
July 1st, 2010It is only for ……..
When SQUID was used for internet sharing in All MS enviornment respone was :- It is only in the server side , and It is not doing much other than internet sharing.
When using CVS . Explanation was was:- It is only in the version control
When using Linux OS for ORACLE erp . Explanation Oracle works well with Linux
When SAMBA was used for PDC. Explanation was was:- It is only in the server side
When Nagious /ZABBIX was used. Explanation was was:- It is only for monitoring
When SNORT was used. Explanation was :- It is only for IDS
When OpenVPN was used. Explanation was :- It is only for VPN
When ISPConfig was used. Explanation was :- It is only for Web Site management
when Joomla was used. Explanation was :- It is only for Web Site hosting
When Asterisk was used . Explanation was :- It is only for Phone system
When DOTproject was used. Explanation was :- It is only for Project Management
When UltraMonkey was used. Explanation was :- It is only for Load Balancing
When heartbeat was used. Explanation was :- It is only for High Avaliablity
When Amanda/BackuPC was used. Explanation was :- It is only for BackupWhen
When Nuxeo was introduced[Not used live so far] :- It is only for DM
Problem in sharing the HP printer
June 27th, 2010Configuring HP5200 was too simple . I had done only this much . I connected the printer to the server (feodra 12 ) , and switched on the server
The printer was automatically detected and configured to the system.
From the client side (Fedora 12) I did had problem in connecting to the printer. This was because of name resolution problem + cups
settings
I had to do few steps
# In the server (ie where the printer was connected ) I had to give the necessary sharing option for the CUPS (http://server.mydomain.com:631/
# In the Linux client PC , I had to edit the /etc/hosts file and made entry for the server
Disabling services in Ubuntu
June 22nd, 2010In ubuntu u can use
“update-rc.d -f service remove ” to disable the services when the machine boots up
SSL Notes
June 15th, 2010To generate a RSA key
openssl genrsa -out privkey.pem 2048
To generate a DSA key
openssl dsaparam -out dsaparam.pem 2048
Creating a certificate request
openssl req -new -key privkey.pem -out cert.csr
Creating a self-signed test certificate
openssl req -new -x509 -key privkey.pem -out cacert.pem -days 1095