Day 6 - Shell Scripting & Linux Interview Questions for DevOps Engineers

1. List some commonly used shell commands.

Answer:
“In my day-to-day DevOps work, I mostly use basic operational commands such as:

ls — list files
cp, mv — copy and move files
mkdir, touch — create directories and files
vim — edit files
grep, awk, sed — filtering and text processing
find — search for files
df, du — disk usage
top, ps — process monitoring
tail -f — read logs in real-time

Advanced debugging commands like netcat, traceroute, route I use only during troubleshooting.”

2. Write a shell script to list all processes.

Script:

#!/bin/bash
ps -ef

If asked to print only process IDs:

ps -ef | awk '{print $2}'

3. Write a script to print only ERROR lines from a remote log file.

Answer:
“Using curl, grep, and a pipe.”

Example:

curl -s <remote_log_url> | grep "ERROR"

4. Write a script to print numbers divisible by 3 and 5 but NOT by 15 (range 1–100).

Script:

#!/bin/bash
for i in {1..100}
do
    if { [ $((i % 3)) -eq 0 ] || [ $((i % 5)) -eq 0 ]; } \
       && [ $((i % 15)) -ne 0 ]; then
        echo $i
    fi
done

5. Script to count number of occurrences of ‘s’ in “Mississippi”.

Script:

#!/bin/bash
word="Mississippi"
echo "$word" | grep -o "s" | wc -l

6. How will you debug a shell script?

Answer:
“By enabling debug mode using set -x at the top of the script.
It prints each command before execution.”

set -x

7. What is crontab? Provide an example.

Answer:
“Crontab is used to schedule recurring jobs in Linux, like backups, reports, cleanup, etc.”

Example: run a script every day at 6 PM

0 18 * * * /home/ubuntu/report.sh

8. How do you open a file in read-only mode with Vim?

vim -R filename

9. Difference between soft link and hard link.

Hard Link

Points directly to the inode.
Original and link are identical.
If original file is deleted, data remains.
Cannot link directories.
Cannot link across different filesystems.

Soft Link (Symbolic Link)

Acts like a shortcut referencing the path.
If original file is deleted, soft link breaks.
Can link directories.
Can link across filesystems.

Example:
Python → python3 alias is created using soft links.

10. Difference between break and continue.

break

Exits/terminates the loop completely.

continue

Skips the current iteration and continues loop execution.

Example use cases:

break: Stop when a condition is met.
continue: Skip unwanted values (e.g., skip multiples of 15).

11. Disadvantages of shell scripting.

Answer:

Not statically typed → variables can cause runtime errors.
Difficult to debug large scripts.
Poor error handling compared to modern languages.
No portability for platform-specific commands.
Complex logic becomes unreadable.
Slower execution vs. compiled languages.

12. Types of loops in shell scripting.

for loop – iterate over range, list, or output
while loop – run until a condition is false
until loop – run until condition becomes true
select loop – menu based input

13. Is Bash statically or dynamically typed?

Answer:
“Bash is dynamically typed. Variables do not require data type declarations, and types are determined at runtime.”

Day 6 - Shell Scripting & Linux Interview Questions for DevOps Engineers

Comments

DevOps

Day 7 - Git and GitHub

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1. List some commonly used shell commands.

2. Write a shell script to list all processes.

3. Write a script to print only ERROR lines from a remote log file.

4. Write a script to print numbers divisible by 3 and 5 but NOT by 15 (range 1–100).

5. Script to count number of occurrences of ‘s’ in “Mississippi”.

6. How will you debug a shell script?

7. What is crontab? Provide an example.

8. How do you open a file in read-only mode with Vim?

9. Difference between soft link and hard link.

Hard Link

Soft Link (Symbolic Link)

10. Difference between break and continue.

break

continue

11. Disadvantages of shell scripting.

12. Types of loops in shell scripting.

13. Is Bash statically or dynamically typed?

Command Palette

Comments

DevOps

Day 7 - Git and GitHub

More from this blog

1. List some commonly used shell commands.

2. Write a shell script to list all processes.

3. Write a script to print only ERROR lines from a remote log file.

4. Write a script to print numbers divisible by 3 and 5 but NOT by 15 (range 1–100).

5. Script to count number of occurrences of ‘s’ in “Mississippi”.

6. How will you debug a shell script?

7. What is crontab? Provide an example.

8. How do you open a file in read-only mode with Vim?

9. Difference between soft link and hard link.

Hard Link

Soft Link (Symbolic Link)

10. Difference between break and continue.

break

continue

11. Disadvantages of shell scripting.

12. Types of loops in shell scripting.

13. Is Bash statically or dynamically typed?