In my previous article I have given the top 20 interview Questions and answers for technical support. In this article I would like to focus on Unix Interview questions which i already given for application support. This article will focus on 20 Unix Production support Interview questions with answers and examples. These interview questions are important for the production support engineer who are working on supporting application.You can also refer Unix application support interview questions.You can also see the youtube video clicking here.
Unix Production Support Interview Questions and answers :
Question 1: What is Unix? (100% asked Unix Production Support Interview Questions )
Answer :
Unix is a powerful and versatile multi-user, multitasking operating system developed in the late 1960s. It provides a robust command-line interface and forms the basis for many modern operating systems.
Question 2: Explain the difference between Unix and Linux.
Answer :
Unix is a family of operating systems, including commercial ones, whereas Linux is an open-source Unix-like operating system. An example of Unix is AIX, while Linux includes distributions like Ubuntu and CentOS.
Question 3: What is a shell in Unix?
Answer :
A shell is a command-line interpreter that allows users to interact with Unix. An example of a Unix shell is the Bourne Shell (`/bin/sh`) or the Bash Shell (`/bin/bash`).
Question 4: How do you list files in a directory using the command line?(100% asked Unix Production Support Interview Questions )
Answer :
You can use the `ls` command to list files in a directory. For example, to list files in the current directory:
“`bash
ls
“`
Question 5: What is the purpose of the `chmod` command?(100% asked Unix Production Support Interview Questions )
Answer :
The `chmod` command is used to change file permissions in Unix. For instance, to make a file executable, you can use:
“`bash
chmod +x filename
“`
Question 6: Explain the difference between a soft link and a hard link.
Answer:
A soft link (symbolic link) is a reference to a file by its path, while a hard link is another reference to the same file data on disk. Example:
“`bash
# Creating a soft link
ln -s originalfile softlink
# Creating a hard link
ln originalfile hardlink
“`
Question 7: What is a daemon in Unix?
Answer :
A daemon is a background process that runs without user interaction. An example is the `httpd` daemon for serving web pages.
Question 8: How do you check the disk usage on a Unix system?(100% asked Unix Production Support Interview Questions )
Answer :
Use the `df` command to check disk usage. For example, to display disk usage for all mounted filesystems:
“`bash
df -h
“`
Question 9: Explain the significance of the `/etc/passwd` file.
Answer:
`/etc/passwd` stores user account information, including usernames and encrypted passwords. Here’s an example entry:
“`bash
john:x:1001:1001:John Doe:/home/john:/bin/bash
“`
Question 10: What is the purpose of the `grep` command?
Answer:
The `grep` command is used to search for text patterns in files. For instance, to find the word “error” in a log file:
“`bash
grep “error” logfile.log
“`
Question 11: How do you kill a running process in Unix?
Answer :
To terminate a process in Unix, you can use the `kill` command followed by the process ID (PID). For example, to kill a process with PID 1234:
“`bash
kill 1234
“`
Question 12: What is the `cron` job scheduler in Unix?
Answer :
`cron` is a utility in Unix for scheduling tasks to run at specified times. For instance, to schedule a script to run daily at midnight:
“`bash
0 0 * * * /path/to/script.sh
“`
Question 13: Explain the difference between a process and a thread.
Answer :
A process is an independent program with its own memory space, while a thread is a smaller unit of a process that shares its memory space. Processes are isolated from each other, while threads within the same process share resources. For example, a web server process can have multiple threads handling different client requests concurrently.
Question 14: How do you redirect the output of a command to a file?
Answer :
You can redirect the output of a command to a file using the `>` operator. For example, to save the output of a command to a file called `output.txt`:
“`bash
command > output.txt
“`
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Question 15: What is the purpose of the `tar` command?
Answer :
The `tar` command is used for archiving and compressing files in Unix. For instance, to create a compressed tarball of a directory:
“`bash
tar -czvf archive.tar.gz directory/
“`
Question 16: What does the `ps` command do?
Answer :
The `ps` command is used to list currently running processes. For example, to list all processes running on the system:
“`bash
ps aux
“`
Question 17: How do you set environment variables in Unix?
Answer :
You can set environment variables in Unix using the `export` command. For example, to set the `JAVA_HOME` environment variable:
“`bash
export JAVA_HOME=/path/to/java
“`
Question 18: What is the `ssh` command used for?
Answer :
The `ssh` command is used for secure remote login and execution of commands on remote machines. For example, to connect to a remote server:
“`bash
ssh username@remote_server
“`
Question 19:Explain the purpose of the `top` command.
Answer :
The `top` command provides real-time information about system processes, memory usage, and CPU usage. It’s often used to monitor system performance and identify resource-intensive processes.
Question 20: How do you check for the existence of a file in a shell script?
Answer :
In a shell script, you can check for the existence of a file using the `-e` flag with the `test` command or the `-f` flag for regular files. For example, to check if a file named `myfile.txt` exists:
“`bash
if [ -e myfile.txt ]; then
echo “File exists.”
else
echo “File does not exist.”
fi
“`
These are all most asked Unix Production Support Interview Questions with answers. If you lke this article or if you have any issues with same kindly comment in comments section.
Really useful questions
Thanks Amar