Question { 11171 }

How can I know my linux os is 32 bit or 64 bit?
and How can i know my CPU is 32 bit or 64 bit in linux
machine environment.?

Answer

getconf LONG_BIT

Question { CTS, 9646 }

I want to kill zombie process, but with using kill 9 i
cannot kill that process? can u tell other commands?

Answer

Zombie :
This is the dead process. We can not kill this directly this
process. Since zombie is the child process created by some
parent process.
so sometimes parent process will leave it for future
process. So need to send SIGCHILD signal to parent process
to kill zombie.

command:

" kill -s SIGCHLD " ; ppid --> parent process id.

From this way we can kill zombie processes.

Is This Answer Correct ?

7 Yes

2 No

Question { Google, 16588 }

In my linux machine, i lost /etc/passwd file
and /etc/shadow file, then how can i recover it?

Answer

Normally in linux we must have backup by default for
/etc/passwd and /etc/shadow files

/etc/passwd ---> /etc/passwd-
/etc/shadow ---> /etc/shadow-

from there we can copy or restore. If both are not available.
Then follow below steps:
1. reboot
2. Single user mode [ single init=/bin/bash ]
3. pwconv
4. check /etc/passwd and /etc/shadow files are there
5. sync
6. init 3 or reboot with init 3

Question { IIHT, 20446 }

Difference between swap partition and swap file?

Answer

SWAP Partition :

Swap partition is the double the RAM size. This partition
must be create at the time on linux installation.
Whenever RAM is FULL that time space will be taken from SWAP
partition which is available in HDD parmantelly.

SWAP File:

Swap file can be created after the installation any time.
Swap files are normally slower than SWAP partition.
This we can set as temporary purpose. For quick access the
file or data can create SWAP files.

Question { 11385 }

How to monitor ports in a linux machine, with single
command?

Answer

netstat -ant

Question { 6324 }

What is the status code 403,404 represented in apache
server?

Answer

403 --> Forbidden [ This request is legal one but web server
is refusing to respond to it, ]
404 --> Page Not Found [ Web page not available in
webserver, may be available in future ]

Question { 9959 }

I want to see how many interfaces(ethernet cards) are
working using single command?

Answer

lot of single commands:

ifconfig
mii-tool
arp
iftracf

Question { NetEnrich, 11295 }

I want to built a fire wall using iptables. My condition is
" inbound to 192.168.0.2 with a port of 80 from
172.168.0.1 should accept"

Answer

Command:
iptables -i INPUT -t filter -p tcp -s 172.168.0.1 -d
192.168.0.2 --dport 80 -j ACCEPT

Description:
-i --> Match the INPUT or inbound
-t --> Table name here default is filter
-p --> Protocol
-s --> Source IP
-d --> Destination IP
--dport --> Port number
-j --> Condition.

Question { Wipro, 12882 }

I know ssh, telnet, dns,apache all are worked on TCP/UDP
but i want to know any one service which are working on UDP
only?

Answer

Use the below command to check services only running on UDP :

netstat --udp --listening --program

Question { IBM, 12560 }

Q. If we transfer 100 files by ftp to remote server, how to
know the files are successfully transfer or some file are
not transferred ?

Answer

Wait up-to ftp transfer complete. Once completed, go to the
downloaded location in your system and use below command

" ls | wc -l "

Then compare with how many files originally needs to be
transferred from ftp server.

if 100 = 100 then all transferred fine.

Question { Oracle, 14091 }

difference between nfs soft and hard mouniting points?

Answer

Hard : When ever nfs servers goes down, it will wait up-to
nfs server will come online and then start working.
It will not unmounted till user manually unmount the mount
point.

Soft : When ever nfs servers goes down, it will report the
error message after 3 attempts or mentioned time of attempts.
It will unmonut automatically whenever nfs server goes down
without user interaction.

Question { CSS, 28118 }

what are the linux boot files?

Answer

Kernel and init.d files.

Both will be initiated in grup.conf file.

[root@localhost grub]# cat grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making
changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to
/boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/sda2
# initrd /initrd-version.img
#boot=/dev/sda
default=1
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux AS (2.6.9-42.ELsmp)
root (hd0,0)
kernel /vmlinuz-2.6.9-42.ELsmp ro root=LABEL=/
initrd /initrd-2.6.9-42.ELsmp.img
title Red Hat Enterprise Linux AS-largesmp (2.6.9-42.ELlargesmp)
root (hd0,0)
kernel /vmlinuz-2.6.9-42.ELlargesmp ro root=LABEL=/
initrd /initrd-2.6.9-42.ELlargesmp.img
title Red Hat Enterprise Linux AS-up (2.6.9-42.EL)
root (hd0,0)
kernel /vmlinuz-2.6.9-42.EL ro root=LABEL=/
initrd /initrd-2.6.9-42.EL.img

Question { IBM, 18957 }

what is the command for finding the higest memory occupied
file in linux?

Answer

find -name "*" -size +

for example :
find -name "*" -size +10000k

Is This Answer Correct ?

3 Yes

2 No

Question { HCL, 26961 }

what is the command to uninstall processes in linux?

Answer

rpm -ev

To Uninstall a software or package or processes.

Is This Answer Correct ?

1 Yes

3 No

Question { 18560 }

in redhat Linux wat is the command to check at ahich date
and time file was created?

Answer

ls -l

for example:

[root@S30U15VA2 ~]# ls -l
total 256084
-rw-r--r-- 1 root root 1981 Jan 30 2007 anaconda-ks.cfg


Here Jan 30 is the file created time.