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There are 7 TYPES of network BOND in Linux – mode=0 (balance-rr), mode-1 (active-backup),

       mode=2 (balance-xor), mode=3 (BROADCAST), mode=4 (802.3ad), mode=5 (balance-tlb),

       mode=6 (balance-alb)

For this access the individual COMMAND’s manual PAGE. For instance, to know the DESCRIPTION of

     CAT command, type

man cat

This will display a description of the SAID command.

There are 80 system calls in Unix that are used to control processes, MANAGE FILESYSTEM and for inter-process COMMUNICATION. System calls occur in the KERNEL.

There are three modes – command mode, INSERT mode and LAST line or escape mode.

USE the command apt-get as –

        apt-get --purge remove [FILENAME]

USE chmod 777 to GIVE FULL permission to READING, write and execute.

• Ifconfig – configure interface parameters of the network.
• dig – performs DNS lookups to display a result obtained from name servers.
• traceroute – prints the route that the packets take to the network host.
• nslookup – queries internet DOMAIN name servers.
• telnet – connect DESTINATION port if the connection between hosts is working fine
• netstat – reviews each network connection and the open sockets.
• w – writes (prints) CURRENT ACTIVITIES and processes by each user.
• scp – secure copy the files from and to another host in the network.
• ifup/ifdown – enable or disable the network interface respectively.
• nmap – checks for the opened port on the server

A program that gets executed in the background because of the occurrence of a specific event, process or condition. Daemon processes are managed by the Kernel. The operations are given unique PIDS.

Symbolic LINK :-

• links the libraries
• ensures that the FILES are in their place without the ORIGINAL being COPIED or MOVED.

For enhanced security, a shadow copy of the PASSWORD file is made, which stores hashed passwords of all the users. The hashed password is a long string of characters, GENERATED based on the HASHING method used.

Read further for more questions on security in our LIST of Linux interview questions.

Puppet is a CONFIGURATION MANAGEMENT tool. It is USED to

• Deploy, configure and manage servers,
• Define and MONITOR unique configurations for each host
• Scale-up and scale-down machines dynamically
• Provide control over configured devices to PROPAGATE changes in a centralized manner

GRAPHICAL User Interface or GUI MAKES it easier for a LINUX user to execute programs via a desktop, similar to Windows. The desktops in Linux are KDE, Java, GNOME.

Idconfig is a command that creates the required links and cache to the most RECENTLY shared libraries that are present in the directories SPECIFIED in the

• command LINE,
• the file /etc/ld.so.conf,
• the TRUSTED directories /LIB and /usr/lib

It is an environment VARIABLE that contains a list of paths that are USED to resolve the LIBRARY dependencies at run-time (dynamic LIBRARIES). This path is checked before the STANDARD paths /lib or /usr/lib.

Use df [OPTIONS] [DEVICES] to check hard drive space.

Example –

df -H /test/tmp gives OUTPUT as

• OPEN the command PROMPT using Ctrl+Alt+T
• If your file does not have to execute permission, add the same chmod +X /root/home/your file.sh
• Run the script by typing /root/home/your file.sh and press ENTER.

You can USE the key combination Ctrl+Alt+T to OPEN a COMMAND prompt in Linux.

VIRTUAL desktop provides secure access to LINUX VDI EVEN from non-Linux devices like Windows. This HELPS admins manage Windows and Linux APPLICATIONS using one console.

The CORE components of Linux are boot LOADER, kernel, shell, DAEMONS, window MANAGER and X window server.

LINUX has a layered STRUCTURE –

• Hardware - the CPU, RAM, mouse, the keyboard is the hardware
• Kernel - contains device drivers and handles resource allocation, acts as an interface between the hardware and the operating system.
• The standard library of procedures – termed as LIBC, allows the user to communicate with the kernel.
• User applications and standard utilities – the commands for various tasks like computing, MODIFYING files or taking backups, etc.

There are multiple reasons for this –

• Linux gives very low access to its USERS. If there is a virus attack, only a few files will be corrupted not the whole system.
• It is less vulnerable because a user needs complete EXECUTION rights for opening EVEN an email attachment.
• The working environment in Linux is segmented in different environments like Ubuntu, ARCH, Linux Mint, etc. This division gives much protection from the virus.
• Linux uses Iptables which requires advanced privileges to function.

• Multi-tasking is possible without slowing down CPU.
• Offers high security compared to other OSs like WINDOWS, iOS, etc.
• Can be converted from the command line to GUI by installing required packages.
• Open source code with great community and support.
• Can run on different hardware types.
• Hierarchical file system.

Read details about the security features of Linux in the NEXT question of our Linux INTERVIEW QUESTIONS list.

If a Linux server runs out of memory, the KERNEL moves some inactive processes from Linux server to a DISK that acts as the VIRTUAL memory. This disk space is CALLED a SWAP.

An open-source OPERATING system, Linux is CURRENTLY one of the best OSs. It can be considered as software that SITS underneath and communicates with the other software on a computer and passes on requests from those software PROGRAMS to the hardware.

Linux is used because it is –

• Highly stable and secure
• Can be maintained easily
• Can run on any hardware system
• Open source and FREE to use
• Extensive documentation and support

You can kill the PROCESS using –

• kill PID – It is used to kill a PARTICULAR process.
• killall – It is ALSO used to kill all the running processes.