1. What is ldd?
List dynamic dependencies –
print shared library dependencies.
2. What is the command to
uninstall processes in Linux?
rpm –e servicenmae
yum remover servicename
3. What is the command for
finding the highest memory occupied file in Linux?
du –ah / | sort –n –r | head
–n 1
du – estimate file space
usage
-a – write counts for all
files, not just directories
-h – print sizes in human
readable format (eg. 1K 234M 2G)
sort – sort lines of text
files
-n – compare according to
string numerical value
-r – reverse the result of
comparisons
head – output the first part
of files
-n – number of lines
4. What are the Linux boot
files?
1./boot/grub/grub.conf:
contains boot disk parameters
2./etc/fstab: contains File
systems which need to mount at boot time
3./etc/initab: Contains
default run level
4./etc/init.d/rc.d/rcN.d:
This is a dir it contains
5. Difference between swap
partition and swap file?
Swap partition is maintained
as a separate partition. Same swap partition can be used for two OS within single
machine.
Suppose if the system
crashes, there is a chance to recover or it may not corrupt the partition.
Less fragmented.
Where as swap file takes
very less space. We can increase the space very easily, compared to swap
partition. Swap file system fragmented.
If the system crashes then there is a huge
chance to lost the swap file system.
6. A file which is not
deleted by normal user and also root (using rm), for that type of file how we
delete it?
Using chattr command, we
need to change the attributes and then we remove using rm command.
Eg: – chattr -iIu example
rm -rf example
7. Difference between nfs
soft and hard mounting points?
Hard mount option: – If the
client fails to access the server, then the connection hangs and once the
system is up then it will again access the server.
Soft: – If the client failed
to connect the server, it immediately gives the error report and closes the
connection.
8. If we transfer 100 files
by ftp to remote server, how to know the files are successfully transfer or
some file are not transferred?
ftp>mput 1 2 3 …. 100
ftp> ls –l
9. 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?
snmptrap 162/udp
snmptrap – simple network
management protocol trap
snmptrapd is an SNMP
application that receives and logs
10. 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”
iptables –A INPUT –p tcp
–dport 80 –s 172.168.0.1 –d 192.168.0.2 –j ACCEPT
11. I want to see how many
interfaces (Ethernet cards) are working using single command?
ifconfig
12. What is the status code
403,404 represented in apache server?
403 represent forbidden
error, means if a file misses some selinux security context.
404 represent that there is
a cgi script missing or web pages missing.
13. How to monitor ports in
a linux machine, with single command?
nmap localhost
14. In my linux machine, i
lost /etc/passwd file and /etc/shadow file, then how can i recover it?
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
15. what r the different
command to check ram,process and hdd of linux machine
To check ram in your system:
#free
To check process
#ps
#top
To check hdd
#fdisk
#sfdisk -l
16.If i run ls command it
will show me the junk output what is problem and how to resolve it
Set your terminal setting by
stty and before that, export ls command to PATH variable
17. WHAT IS THE MEANING OF
AIX
AIX (Advanced Interactive
eXecutive) is an open operating system from IBM which is based on a version of
UNIX. AIX/ESA was designed for IBM’s System/390 or large server hardware
platform. AIX/6000 is an operating system that runs on IBM’s workstation
platform, the RISC System/6000.
18. Why ls -F dev/log file
output indicate as = sign at end of the file name?
Standard output
19. What is nis server?
NIS is a service that
provides any user on a network with the same working environment irrespective
of the system on that network, which has been used for login purpose.
For example if NIS server is
set up in a single system and configured to hold user accounts and their
passwords and access information. Then any user on that network can login to
his/her account from any system (with nis client running) on that configured
network. This gives a look and feel that the user is logged into his/her own
system. But actually it’s the account on the NIS server that is mounted on the
local sytem user login.
20. What command can you use
to review boot messages?
Dmesg
21. Who invented unix?
Unix was created in 1969 by
Ken Thompson and Dennis Ritchie at Bell Laboratories.
22. Write a cron entry for
the following scenario:- At 10:30 AM for every Sunday of every 1st month of a
quarter.
30 10 * 1-12/3 7
23. What is the difference
between RHEL4 & RHEL5?
RHEL4: No yum server,
Selinux, secure, no cd key
RHEL5: yum server, advanced
selinux, more secure, virtualization
24. What is the command to
make a process to run in the foreground from background?
When the process is running,
press “control+Z”. Now at the command prompt, type “bg”
25. What are the init levels
in Linux?
7 level
No comments:
Post a Comment