How To Access Web Server Through IP Address?
0 comments 12/25/2010 10:12:00 AM Posted by Surendra Kumar AnneLabels: Advanced Servers, DNS Servers, How-To's
How To Configure And Install Sendmail In Linux?
0 comments 12/13/2010 11:55:00 PM Posted by Surendra Kumar AnneLabels: How-To's, Mail Servers
Send mail is one of the old and widely used mail delivery agent/Mail system.
How To Upgrade An Installed Source Package?
0 comments 12/12/2010 10:18:00 PM Posted by Surendra Kumar AnneLabels: How-To's, Package-Mgmt
I have installed a package from source, now I want to upgrade the older version to new version which is available.
How can I upgrade already installed source package on my system?
Ans : This question arises to all the admins who do installation from source package. To upgrade a source package follow the same steps to you have did at the time of first installation through source. Package as shown below..
Step1: unpack the new source code in tmp directory.
#cd /tmp
#tar xvfz packagname.tar.gz
#cd packagename
#./configure –prefix=/path/to/old/installation
#make
#make check
#make install
Step2 : Now check what is the version if its updated to new version for example
If you install squid then execute below command
#squid -v
How To Install Apache Tomcat on Linux(Redhat/Ubuntu)?
1 comments 12/10/2010 09:08:00 PM Posted by Meghana M BhombhoreLabels: Advanced Servers, How-To's
How to install Apache tomcat on Linux(Redhat/Ubuntu)?
What is Apache tomcat?
Ans : ApacheTomcat is an open source web application server which supports J2ee Servlets, JavaServer, Pages(JSP) and API's. Tomcat should not be confused with Apache web server which an HTTP web server.
---Wikipedia.
Some terminology about Apache tomcat.
Apache Tomcat can be configured by editing server.xml file. Those who knows apache web server. This server.xml can be taken as synonimas to httpd.conf file.
Servlet is defined as a way add dynamic content to a Web server using the Java platform. And a servlet container is a compiled, executable program. The servlet container name is tomcat is catalina.
Pre requists for Apache tomcat are
1. java
2. JDK
Step by step for installing Apache tomcat
Note : Avoide installing tomcat from reposatories, always prefer to install it from source downloaded from apache site.
Step1 : Install all the prequistes
Redhat :
#yum install java
Ubuntu :
#apt-get install java
Step2 : Download tomcat source package and uncompress it.
Redhat/Ubuntu
#cd /opt
#wget http://www.trieuvan.com/apache/tomcat/tomcat-6/v6.0.29/bin/apache-tomcat-6.0.29.tar.gz
#tar xvfz apache-tomcat-6.0.29.tar.gz
Step3 : Setup the paths for Catalina and others.
Setting catalina paths
Redhat/ubuntu
CATALINA_HOME=/opt/apache-tomcat-6.0.29
CATALINA_BASE=/opt/apache-tomcat-6.0.29
Setting java paths
Check what java versions are installed in your system
#update-alternatives --config java
This command will display which is default java version used by your machine.
Example output :
# update-alternatives --config java
There are 2 programs which provide 'java'.
Selection Command
-----------------------------------------------
1
/usr/lib/jvm/jre-1.4.2-gcj/bin/java
*+ 2
/usr/lib/jvm/jre-1.6.0-openjdk/bin/java
Enter to keep the current selection[+], or type selection number:
If you see above the default java version is 1.6 so set the path to /usr/lib/jvm/jre-1.6.0-openjdk
JAVA_HOME=/usr/lib/jvm/jre-1.6.0-openjdk
JDK_HOMe=$JAVA_HOME
Step4 : Now start tomcat server
#/opt/apache-tomcat-6.0.29/bin/sartup.sh
Sample output.
Using CATALINA_BASE: /opt/apache-tomcat-5.5.26
Using CATALINA_HOME: /opt/apache-tomcat-5.5.26
Using CATALINA_TMPDIR: /opt/apache-tomcat-5.5.26/temp
Using JRE_HOME:
/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0/
Step5 : By default Apache Tomcat will be hosted onlocalhost : 8080 port by default. So try to access the site with web browser
http://localhost:8080
or
http://localhost:8080
or
http://systemname:8080
Stay tuned to other posts about troubleshooting tomcat installation.
How To Set Java Path In Linux?
0 comments 12/10/2010 08:58:00 PM Posted by Meghana M BhombhoreLabels: How-To's
How to set java path in Linux?
Ans : Check where java is installed by using below command
#update-alternatives --config java
This command will show installed java packages in your machine.
Example output :
# update-alternatives --config java
There are 2 programs which provide 'java'.
Selection ----------------------------------------------- 1 /usr/lib/jvm/jre-1.4.2-gcj/bin/java *+ 2
From above you can see java version in use it. 1.6.
Setting java path(In Temporary way)
#JAVA_HOME=/usr/lib/jvm/jre-1.6.0-openjdk #export $JAVA_HOME
Setting java path (In Permanent way)
Edit ~/.bashrc and place below two lines in that file and save the file.
Vi ~/.bashrc
JAVA_HOME=/usr/lib/jvm/jre-1.6.0-openjdk export $JAVA_HOME
Now save the file and exit, then logout and login to make those changes to reflect.
Command
/usr/lib/jvm/jre-1.6.0-openjdk/bin/java
How To Change The Java Version In Linux?
0 comments 12/10/2010 01:16:00 AM Posted by Surendra Kumar AnneLabels: How-To's
This post is regarding how to change java version if multiple java versions are installed?
Check what are the java versions are installed on your system
#java -version
Example output
OpenJDK Runtime Environment (build 1.6.0-b09)
OpenJDK Client VM (build 1.6.0-b09, mixed mode)
So now I want to change the one version to another version.
If more than one java is installed. Execute below command to see how many java versions are installed? And what is the default version (Default version will be indicated by *)
#update-alternatives --config java
This command will display which is default java version used by your machine..
Example output.
# update-alternatives --config java
There are 2 programs which provided 'java'.
Selection Command
-----------------------------------------------
1. /usr/lib/jvm/jre-1.4.2-gcj/bin/java
*+ 2 /usr/lib/jvm/jre-1.6.0-openjdk/bin/java
Enter to keep the current selection[+], or type selection number:
So if you want to change the java version from 1.6 (now 2 is default version as shown) to 1.4 just press “1” with out quotes.
Please let us know if you know other way of changing java version.
How To Enable Verbose Mode For SSH Logins?
0 comments 12/09/2010 06:43:00 AM Posted by Surendra Kumar AnneLabels: How-To's, SSH, Troubleshooting
How we can login to remote server through ssh?
#ssh user@servername
or
#ssh -l user servername
or
#ssh ip-add
So when you will execute the above command you will get the password prompt. But if you want to see what will happen when you execute ssh command you have to enable verbose or debugging mode. To do this we have to apply -v option at the time of login as shown in below example.
#ssh -v surendra@ftp2.linuxnix.com
root@krishna:/home/surendra# ssh -v surendra_a@ftp2.linuxnix.com
OpenSSH_5.5p1 Debian-4ubuntu4, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to ftp2.linuxnix.com [92.32.56.78] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_4.0
debug1: match: OpenSSH_4.0 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu4
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'ftp2.linuxnix.com' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Next authentication method: keyboard-interactive
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: password
surendra_a@ftp2.linuxnix.com's password:
debug1: Authentication succeeded (password).
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = en_IN
Last login: Thu Dec 9 20:02:47 2010 from 1.23.6.79
After logout
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: free: client-session, nchannels 1
Connection to ftp2.linuxnix.com closed.
Transferred: sent 2072, received 2072 bytes, in 27.7 seconds
Bytes per second: sent 74.8, received 74.8
debug1: Exit status 0
So if you want more verboseness you can use up to 3rd level(-vvv) as shown below
#ssh -vvv surendra_a@ftp2.linuxnix.com
How To Change The Date In Linux?
0 comments 11/25/2010 10:14:00 PM Posted by Surendra Kumar AnneLabels: Basics, How-To's
How can we change the date/time in linux?
Ans : Changing date in linux is bit confusing. If you want to change date in GUI its very much easy and if you want to change it when it comes to CLI its bit hard to remember it.
Date is the command to check whats the present date
#date
To change the date use below command
#date MMDDHHMMYYYY.ss
MM => Two digit month value
DD => Two digit day value
HH => Two digit hour value
MM => Two digit minuite value
YYYY => Four digit year value
ss => Two digit seconds value(very rare we will be using this)
Example1 : I want to change the date to Nov 24 1:36 PM 2010
#date 112413362010
Example2 : I want to change the date to Jan 9th 8:05.04 AM 2010
#date 010908052010.04
Now the date will be changed to your required date.
How To Set A PHP Path In Linux?
0 comments 11/17/2010 11:16:00 PM Posted by Surendra Kumar AnneLabels: How-To's
How can we set PHP path in linux?
Ans : When you install PHP and host some .php files on webserver your web server will not detect it. This is because your Apache server does not know how to interprit PHP files? And and where is php located? To eleminate this issue we have to set the php path in main php configuration file php.ini located in your machine. As the linux is open source and the location of this file differs from different flavors, so better option is to search for php.ini file as shown below.
find / -iname php.ini
or some common locations for Redhat and Ubuntu are shown below
For Redhat flavors
/etc/php.ini
For Ubuntu Flavors
/etc/php5/apache2/php.ini
To search for include_path and uncomment that before changes.
;include_path = ".:/usr/share/php"
After changes.
include_path = ".:/usr/share/php"
Now save and exit the file. And you have to restart the apache server to detect this settings.
For Redhat
#service httpd restart
For Ubuntu
/etc/init.d/apache2 restart
Now start coding in PHP and enjoy the php scripting.
How to implement ip forwarding in Linux
2 comments 10/19/2010 06:35:00 PM Posted by Surendra Kumar AnneLabels: How-To's, Proxy Servers, Routing
Why we require IP forwarding on a Linux machine?
Ans : We require IP forwarding on a Linux machine because to make it as a router or proxy server to share one internet connection to many client machines.
Let me explain how this will work with small example.
You have 2 machines which are in different network(PC1 in 10.0.0.0/255.0.0.0 network and PC2 in 192.168.0.0/255.255.255.0 network) and connected with a Linux machine(which is having two network interfaces). The IP address is as follows..
PC1: 192.168.0.1/255.255.255.0 default gateway:192.168.0.2
PC2: 10.0.0.1/255.0.0.0 default gateway:10.0.0.2
Linuxbox eth0 : 192.168.0.2/255.255.255.0
eth1 : 10.0.0.2/255.0.0.0
and Linux machine is having two LAN cards which are connected to both the

Ans : The answer to this question is No.
How to make PC1 to communicate with PC2?
Ans : The answer is enable ip forwarding on Linux machine. Some times this is called as bridging two networks.
To achieve IP forwarding we have to edit /etc/sysctl.conf as shown below. Open sysctl.conf and change the value of “net.ipv4.ip-forard” from 0 to 1 and save the file
#vi /etc/sysctl.conf
net.ipv4.ip-forard = 0
to
Once its done still you are not able to ping from PC1 to PC2. We have to restart the linuxbox to take this update to kernel.
Why to restart if its a production machine try below command to make your linuxbox aware of IP forwarding with out a restart.
echo 1 > /proc/sys/net/ipv4/ip-forward
Now try to ping from PC1 to PC2 which will ping successfully.
Equivalent Tool For WINscp in Linux
0 comments 10/18/2010 07:43:00 PM Posted by Surendra Kumar AnneLabels: Administration, Basics, How-To's
Is there any tool which is equivalent to do what WINscp does in Windows?
In Linux we have one utility called nautilus to do this work.
Redhat:
#yum install nautilus
Ubuntu:
#apt-get install nautilus
Try to access Nautilus as shown below in screen by screen shot manner
Go to places and the slect connect to server.

Then specify the server ip, port where ssh service is running, user name to connect, then press connect

Now it will ask for the user’s password, enter the password and connect it.

This screen shot show the remote server content.

How To Assign Default Gateway In Linux?
0 comments 7/09/2010 07:38:00 AM Posted by Meghana M BhombhoreLabels: Basics, General, How-To's
How to Assign Default gateway in linux?
Ans : In linux Default gateway is set through route command or GUI tools.
Through Route command
#route add default gw default-gateway
Example :
#route add default gw 192.168.0.1
Here 192.168.0.1 is the default gate of my system.
Through GUI tools
Use system-config-network in terminal or GUI to set up default gateway.
How To View Default Gateway In Linux?
0 comments 7/07/2010 09:11:00 AM Posted by Meghana M BhombhoreLabels: Basics, How-To's
This is asked in some of the interviews. We can get default gateway information in linux in many ways. Such as viewing network card file or executing a command.
To see default gateway by view network interface card file content.
#cat /etc/sysconfig/networking/devices/interface-no
Example :
[root@example ~]# cat /etc/sysconfig/networking/devices/ifcfg-eth0
# Intel Corporation 82546EB Gigabit Ethernet Controller (Copper)
DEVICE=eth0
BOOTPROTO=none
HWADDR=00:02:a5:4c:af:99
ONBOOT=yes
TYPE=Ethernet
NETMASK=255.255.255.0
IPADDR=10.200.0.21
GATEWAY=10.200.0.1
Through route command
route
Example:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.0.0 * 255.255.255.0 U 0 0 0 eth1
10.78.0.0 * 255.255.255.0 U 0 0 0 eth0
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
default 10.200.0.1 0.0.0.0 UG 0 0 0 eth0
Through ip route command
ip route
Example :
[root@example ~]# ip route
192.168.0.0/24 dev eth1 proto kernel scope link src 192.168.0.1
10.78.0.0/24 dev eth0 proto kernel scope link src 10.78.0.21
169.254.0.0/16 dev eth1 scope link
default via 10.200.0.1 dev eth0
Through netstat command
netstat -r
Example:
[root@example ~]# netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.0.0 * 255.255.255.0 U 0 0 0 eth1
10.78.0.0 * 255.255.255.0 U 0 0 0 eth0
169.254.0.0 * 255.255.0.0 U 0 0 0 eth1
default 10.200.0.1 0.0.0.0 UG 0 0 0 eth0
Note:For any system/server there will be only one default gateway, if suppose if you assign two default gateways to your machine, your system will not come to know where to send the packets.
How To Assign Or Change Hostname In Linux?
0 comments 7/05/2010 07:46:00 AM Posted by Meghana M BhombhoreLabels: How-To's
Computers are assigned with a name as we do for humans beings. This is called hostname in computer world. So how to assign a hostname to a Linux system? Its very much simple. Before doing this we should know every task in Linux can be done in two ways :
1. Temporary way(once you boot your system the changes made in this way will go away)
2. Permanent way(Changes made in this way will be retained even after rebooting of the system).
Before changing the hostname, check what is your present system name by using hostname command
#hostname
This command will show present system name.
Now we will see how to assign a host name to a linux machine in both(temporary as well as permanent) ways.
Temporary way : Use hostname command to change the host name
#hostname your-system-name
Example : #hostname office-laptop.example.com
Permanent way : Change hostname in Redhat/CentOS/Fedora :
Edit /etc/sysconfig/network file, use HOSTNAME variable in that file to denote hostname.
#vi /etc/sysconfig/network
HOSTNAME=office-laptop.example.com
Save the file and exit
Then your hostname is changed permanently to your desired name.
Change hostname in Ubuntu/Debian : Edit /etc/hostname, just write down what is your hostname in to that file.
#vi /etc/hostnameoffice-laptop.example.com
Save the file and exit
Then your hostname is changed permanently to your desired name.
How To Find Web Server Type Running On A Linux Or Windows Machine?
0 comments 6/16/2010 06:38:00 AM Posted by Meghana M BhombhoreLabels: How-To's, Web Servers
How to find web server type running on a Linux or windows machine? Is there any linux command to get the details?
Ans : Yes its possible in Linux by using curl(client for URL) command. To find which web server is running on a machine use blow command.
#curl -I www.linuxnix.com
# curl -I itig
HTTP/1.1 200 OK
Via: 1.1 us-PROXY1, 1.1 us-PROXY2
Connection: close
Proxy-Connection: close
Expires: Mon, 1 Jan 2001 00:00:00 GMT
Date: Mon, 14 Jun 2010 03:26:55 GMT
Content-Type: text/html; charset=utf-8
Server: Apache/2.2.3 (Red Hat)
X-Powered-By: PHP/5.1.6
Set-Cookie: b2933756b1f0288a74dd630e51954bff=5sl7jaqpgliambi2fq7q3ailv6; path=/
P3P: CP="NOI ADM DEV PSAi COM NAV OUR OTRo STP IND DEM"
Last-Modified: Mon, 14 Jun 2010 03:26:55 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
In the above out put we can see server as Apache 2.2.3.
cURL is an excelent tool to do many thing such as
1. File transfers(FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, LDAP, LDAPS, FILE, IMAP, SMTP, POP3 and RTSP)
2. Can understand SSL certificates
3. Can understand Proxies
4. Can understand Cookies
5. User+password authentication (Basic, Digest, NTLM, Negotiate, kerberos...)
6. File transfer resume
7. Proxy tunneling etc..
How To Play WMV,WMA, MP3 Files In Linux?
0 comments 6/14/2010 06:51:00 PM Posted by Surendra Kumar AnneLabels: Audio, How-To's, Videos
By default most of the Linux systems will not support any of the mention formates. In order to play these files in Linux we require to install mplayer or vlc. My favourite one is VLC(VideoLAN Client). With which you can play most of the media files and even we can play streaming video and audio files. VLC uses ffmpeg codecs back end to convert/play many formats.
VLC support below formats :
3GP(.3gp) ==> 3rd generation phone format, This video format is good for mobile phones.
AIFF/ASF(.asf, .wmv) ==> These are windows proprietary format, ASF(Active Streaming Format) is used for streaming purpose and wmv(Windows media video) for playing windows videos.
AU(.au) ==> Simple Audio file introduced by Sun micro systems.
AVI(.avi) ==>AVI(Audio video interleave) ==> This is one more format developed by MS. Due to separation of Audio and Video the file size is less when compared to normal WMV files, So most of the times when you download movies from torrents they are in AVI.
FLV (.flv) ==> FLash Video, which is used for streaming again. For example the popular video site Youtube.com uses this format to play videos for users.
MOV(.mov) ==> Movie file format which is default format in Mac OS.
MP4(.mp4) ==> Compressed format for Audio, The songs which are stored in mp4 occupies less space then mp3. So many users when they want to listen to songs on their mobile phones uses this format to store songs.
OGG(.ogm, .ogg) ==>Again a streaming video/audio format MKV(.mkv, .mka).
MPEG-2/TS(.ts, .mpg) ==> A Video format.
MPEG-2/ES, PS, PVA, MP3(.mpg, .mp3, .mp2) ==> Audio format
NSC(.nsc)
NSV(.nsv)
Nut(.nut)
Real(.ra, .ram, .rm, .rv , .rmbv) ==> Real media formats, previous versions did not support will. But now this format is supported well.
Raw(a52, dts, aac, flac, .dv, .vid)
True Audio Codec(.tta, .tac)
Ty Tivo(.ty)
Wav(.wav, .dts)
Xa(.xa)
To install in VLC in Redhat :
#rpm -ivh vlc
To install vlc in Ubuntu :
apt-get install vlc
Once you install vlc will be there in applications -->Sound and Video in menu. Just open any mp3/video file with VLC and enjoy.
These days people are using VLC extensively for playing their Video/Audio files. This download counts are huge.
Find Memory Or RAM And Swap Usage In Linux
0 comments 5/11/2010 12:04:00 PM Posted by Surendra Kumar AnneLabels: How-To's, Process-Mgmt
RAM plays an important role in the performance of a system. So we should monitor this memory usage to troubleshoot system. free is the basic command to get details of RAM and swap usage.
#free
Example :
# free
total used free shared buffers cached
Mem: 3059872 2842016 217856 0 33936 2012684
-/+ buffers/cache: 795396 2264476
Swap: 2000052 67672 1932380
When you see its giving total size, used and free size in bytes. If you want to see in MB specify
-m option in free
#free -m
Example :
# free -m
total used free shared buffers cached
Mem: 2988 2784 203 0 33 1974
-/+ buffers/cache: 776 2211
Swap: 1953 66 1887
Any other commands to check RAM?
The answer for this is yes.
1. Use proc file system to get detailed RAM usage of the system.
#cat /proc/meminfo
2. Use top command to see RAM usage
So with top too you can see RAM usage live.
How To Find And Remove Core Files In Linux?
0 comments 5/11/2010 11:09:00 AM Posted by Surendra Kumar AnneLabels: Administration, How-To's
What is a"Core file" ? Ans : A core file is created when a program is crashed/stoped abnormally due to some bug. This will be huge size which contains all the memory info, crash info which is used for programmers to debug the issue and find a solution or patch to that bug.
Why we system administrators are interested in that core files?
Ans : This is because of their size. As we do monitoring of systems on daily basis but suddenly your disk is full one day when you came to office, you are total blank thinking how come disk is full though there is no much user activity etc. So core files are one reason which will eat up our disk. Which you have to check for when sudden disk activity is observed.
How to find core files ?
#find / -name core
This find command will search entire filesystem for core files.. once you find them use rm command to remove those files..
#rm -rf core
So how it got its name?
A core dump file gets its name from an old memory technology using tiny magnetic cores for storage.
How To Kill Defunct Or Zombie Process?
1 comments 5/08/2010 09:20:00 PM Posted by Surendra Kumar AnneLabels: How-To's, Process-Mgmt
A "defunct" processes is also known as a "zombie" processes. A Zombie process is referred as dead process which is receding on your system thought its completed executing. In one shot we can say its a dead processes. This process will be in your process table and consuming your memory. Having more defunct process will consume your memory which intern slows your system. We have to kill the defunct process in order to free RAM and make system stable.
Why defunct process are created?
Ans : When ever a process ends all the memory used by that process are cleared and assigned to new process but due to programming errors/bugs some processes are still left in process table. These are created when there is no proper communication between parent process and child process.
Some FAQ?
1. How to find a defunct process?
And : Grep defunct value in ps -ef output
#ps -ef grep defunct
2. How can i kill a defunct process?
And : Just use kill command
#kill defunct-pid
3. Still not able to kill?
Ans : Then use kill -9 to force kill that process
#kill -9 defunct-pid
4. Still have an issue in killing it?
Ans : Then try to kill its parent id and then defunct.
#kill parent-id-of-defunct-pid
Then
#kill -9 parent-id-of-defunct-pid
5. Still having defunct?
Ans : If you still find defunct process eating up RAM then last and final solution is to reboot your machine.
6.What is orphan process?
Ans : An orphan process is said to be a process which runs though parent process is terminated, these process do not know what to do and when to terminate.
7. What is difference between orphan and defunct processes?
Ans : A defunct process is a dead process where there is no execution happening where as orphan process is a live process which is still in execution state but don't have parent process
I am having a system which daily creates defunct process, I cannot sit and kill these process on daily basis.
How to get rid of this problem?
Ans : Just write a shell script to grep defunct process and kill them by putting this script in corntab.





