Interview Question & Answer — Linux-1

❓What is the boot process in Linux?

The Linux boot process is divided into six high-level stages:

• BIOS — Basic Input/Output System executes MBR
• MBR — Master Boot Record execute GRUB
• GRUB — Grand Unified Bootloader executes Kernel
• Kernel — Kernel executes /sbin/init
• Init — Init executes runlevel programs
• Runlevel — Runlevel programs are executed from /etc/rc.d/rc*.d/

buymeacoffee ☕ 👈 Click the link

❓How can you create a zero-size file in Linux?

Shell command $ touch filename results in a zero-byte file filename.

❓What are 𝘀𝗼𝗳𝘁 𝗹𝗶𝗻𝗸𝘀 and 𝗵𝗮𝗿𝗱 𝗹𝗶𝗻𝗸𝘀 in Linux? How do you create them? What are the differences between these two types of links?

A “soft link” takes more, as it has an inode, and file contents (the path to the target file) it also has the name in the directory.

Softlink 👈

A “hardlink” only exists in the name in a directory- and specifies the inode number of the file.

Hardlink 👈

ln  [original filename] [link name] --> Hard link create
ln  -s [original filename] [link name] --> Soft link create

Hardlink : Filename => Inode <= My hard link

Softlink : inode <===file name <==soft link

❓What is the first line typically written in a shell script? What is its meaning? What happens if this line is omitted, and how do you run the script in such a case?

It is the first line of the script that would dictate which program to use. The first line starts with the sequence of two characters #! that is called “shebang”. This is followed by the program that tells the operating system which interpreter to use to parse the rest of the file.

#! just happens to be human readable, but that is not required.

❓How can you run a shell script in the background in Linux?

& Symbol

Another method to run a process in the background is by appending the ampersand symbol & to the command you execute.

script.sh &
command &

❓What is a 𝗰𝗿𝗼𝗻𝘁𝗮𝗯 in Linux? Explain how it works and how to configure and schedule a job using crontab.

Crontab, which is short for cron table, is a file containing the schedule of various cron entries that should be run at specified times.

Another way of describing crontab is as a utility that enables tasks to run automatically at regular intervals in the background by the cron daemon.

Crontab → Scheduling tasks to be executed sometime in the future.

Refer Crontab link

1. Write a Script (Optional) This section explains how to create an example script.
2. Create or Edit Crontab File. Open the crontab configuration file for the current user by entering the following command: crontab -e.
3. Create the Cron Job.
4. Output (Optional).
5. Save.
6. Check Active Cron Jobs.

❓How do you allow ports in Linux?

sudo ufw allow 53/tcp

❓How do you troubleshoot a remote server that is experiencing issues?

1. Check if the Remote Desktop service is running on the server.
2. Check if the server’s firewall is blocking Remote Desktop connections.
3. Check if the server is configured to allow Remote Desktop connections.
4. Check if the server’s network settings are correct.