Wednesday 22 April 2015

linux interview questions FOR RHCE

Which version of RHEL officially supports LUKS encryption?

From version 6 or higher LUKS encryption is officially supported by RHEL.

What is the default virtualization technology for RHEL6 ?

Default virtualization technology is KVM.

Can you configure KVM Virtual machine on 32 bit system ?

No, KVM virtualization requires at least 64 bit system.

What is default mode of SELinux during the installation of RHEL ?

  • In RHEL5 you have to choose the mode which you want.
  • From RHEL6 default mode is Enforcing during the installation.
However you can change the mode of SELinux after installation, only difference between RHEL5 and RHEL6 is that in RHEL5 asks you to choose the mode while RHEL6 does not let you to choose the mode during the installation.

Which remote management service is allowed through the default firewall and by default installed in RHEL?

By default SSH is always installed in RHEL. SSH uses port 22 which is allowed through the default firewall rules.

Which standard directory is used by vsFTP server for file sharing ?

Default Standard directory for ftp is /var/ftp/pub.

Which standard directory is used by Apache web server for HTML files ?

standard directory for HTML files is /var/www/html

What is the default partition layout during the installation ?

Default partition Layout is the LVM.

Which necessary partition cannot be a part of logical volume group ?

boot partition cannot be a part of logical volume group. You must have create it as a regular partition.

Which partitions are recommended for custom layout of partition ?

  • /
  • /boot
  • /home
  • swap

What step during the installation could you take to prevent a program from creating temporary files that fill up the entire space ?

You can create a separate /tmp partition prevents a program from creating temporary files that fill up the entire filesystem.

What is the kickstart ?

kickstart is a installation method used in RHEL. A kickstart installation is started from a kickstart file, which contains the answers to all the questions in the installation program.

Name any of two third party distribution based on RHEL6 source code.

CentOS and Scientific Linux

Which Log file contains all installation message?

install.log.syslog file contains all messages that were generated during the installation.

Wednesday 8 April 2015

linux interview questions 1

What is Kerberos used for?

Kerberos is used for secure network logon.
Which partition store system configuration files in Linux system?
/etc partition stores system configuration files in Linux.
What is the purpose of the MD5 option on passwords?
MD5 is an encryption method that encrypts the password before saving.
Name any four general password rules for user account.
  • Include at least eight total characters
  • Use the string in an unrepeated way
  • Avoid use words that can be found in the dictionary
  • Avoid use dates of significance, such as a birthday or anniversary
A better method of password security is to create difficult-to-break passwords that are easy for the users to remember.
What is the alternative method to a GUI installation in Linux ?
Linux provides text base installation as the alternative method of GUI installation.
What is the purpose of the swapon command ?
swapon command is used to activate a already created swap partition. It cannot be used to create a new swap partition.

What is gzip?

gzip is a compression utility created by the GNU project.

What is tar?

tar is an archive utility that is used to create tape backups.
Which is the standard command used to uncompress gzip files?
The standard command used to uncompress gzip files is gunzip.
What is the RPM switch for only installing packages?
The command line switch for installing an RPM is -i.
What is the command used to install an RPM package named demofilename2.2-2.i386.rpm?
The most common command used to install an RPM package is rpm -ivh. Following command will install the given package
#rpm -ivh demofilename2.2-2.i386.rpm
What is the command used to remove an RPM package named demofilename2.2-2.i386.rpm?
The most common command used to remove an RPM package is rpm -evh. Following command will remove the given package
#rpm -evh demofilename2.2-2.i386.rpm
What is the command used to update an RPM package named demofilename2.2-2.i386.rpm?
The most common command used to update an RPM package is rpm -Uvh. Following command will update the given package and remove the old.
#rpm -Uvh demofilename2.2-2.i386.rpm
Which command is used to see which RPM version of gzip was installed on the system?
#rpm -q gzip
Where are the automatically mounted file systems listed?
The automatically mounted file systems are listed in the file /etc/fstab.
While installing the new RPM what common steps should take ?
You should follow these common steps
  • Use RPM tools should be used to query or verify the installed packages to
  • confirm the installation of any previous packages.
  • Check the signature of new package
  • RPM should be installed or upgraded by first using the test mode to verify that it works, and then it should be installed
  • At the end query the RPM and verify the installation of RPM
Which organization controls the official releases and updates of the X Window System?
The X Consortium at www.x.org controls the official release and updating of the X Window System
PPP is most often used to create?
PPP is most often used to create serial point-to-point connections.
When attempting to connect to www.example.com you got unknown host message. Which service is most likely not functioning properly?
DNS
Samba is used to provide support for which protocol?
Samba is used to support the Microsoft SMB/CIFS systems.
What command is used to load a module into the kernel?
The insmod command is used to load a module into the kernel
Name one of the most secure method of remote access.
SSH is the most secure method of remote access
With respect to a Linux system’s RAM, how large should the swap file be?
Generally the size of the swap file should be twice the size of installed RAM.
How would you create a backup of the fstab file to the /backup folder?
Use cp command to create the backup.
#cp /etc/fstab /backup
What command is used to exit the edit mode of VI editor?
The [esc] key is used to exit from the edit mode of VI editor.
What key combination will exit from VI editor and not save the changes made?
Esc + q +! Key combination will exit VI without saving the changes.
What command would you use to create a file system on a new hard drive?
The mkfs command is used to create file systems.

What fstab file do?

The fstab file is used to automatically mount file systems.

What inittab file do?

The /etc/inittab file is used to perform the default state and terminal connections for a Linux system.
What command can you use to verify the current active shell?
The env command will display the current active shell.
Where is the file . bashrc located?
The . bashrc file is usually located in the /home/username directory.
What function does the .bash_profile file perform?
The function of the .bash_profile file is to provide login initialization commands.
What function does the .bash_logout file perform?
The function of the .bash_logout is to provide logout functions
What function does the .bashrc file perform?
The function of the .bashrc file is to provide shell configuration commands.