Why sysadmin skills manage production servers in Linux CLI - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display the current logged-in users on a Linux server.

Linux CLI

who [1]

Drag options to blanks, or click blank then click option'

A-u

B-l

C-a

D-r

Attempts:

3 left

💡 Hint

Common Mistakes

Using -a shows all information but is verbose.

Using -l shows login processes, not users.

Using -r shows runlevel, not users.

The who -u command shows the current logged-in users along with their idle time.

2fill in blank

medium

Complete the command to check disk usage in human-readable format.

Linux CLI

df [1]

Drag options to blanks, or click blank then click option'

A-l

B-a

C-h

D-t

Attempts:

3 left

💡 Hint

Common Mistakes

Using -a shows all filesystems including dummy ones.

Using -l limits output to local filesystems only.

Using -t filters by filesystem type.

The df -h command shows disk usage with sizes in KB, MB, or GB for easy reading.

3fill in blank

hard

Fix the error in the command to restart the Apache web server using systemctl.

Linux CLI

sudo systemctl [1] apache2

Drag options to blanks, or click blank then click option'

Arestart

Benable

Cstatus

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using start only starts the service if stopped.

Using enable sets service to start on boot but doesn't restart.

Using status only shows service status.

To restart the Apache server, use systemctl restart apache2.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each word to its length if length is greater than 3.

Linux CLI

{word: [1] for word in words if [2]

Drag options to blanks, or click blank then click option'

Alen(word)

Blen(word) > 3

Cword.startswith('a')

Dword.upper()

Attempts:

3 left

💡 Hint

Common Mistakes

Using word.upper() as value instead of length.

Using word.startswith('a') as condition instead of length check.

The dictionary comprehension maps each word to its length using len(word) and filters words longer than 3 characters with len(word) > 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase keys to values only if value is positive.

Linux CLI

{ [1]: [2] for [3], [2] in data.items() if [2] > 0 }

Drag options to blanks, or click blank then click option'

Ak.upper()

Bv

Ck

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using item instead of k and v in the loop.

Not converting keys to uppercase.

The comprehension uses k.upper() as keys, v as values, and iterates over k, v in data.items(), filtering values greater than zero.

Practice

1. Why is it important for a sysadmin to have skills in managing production servers?

easy

A. To write novels and stories

B. To keep servers running smoothly and fix issues quickly

C. To design websites and create graphics

D. To manage social media accounts

Solution

1. Step 1: Understand the role of sysadmin skills

   Sysadmin skills focus on maintaining servers and solving technical problems.

2. Step 2: Identify the main goal in production server management

   The main goal is to keep servers healthy and fix problems fast to avoid downtime.

3. Final Answer:

   To keep servers running smoothly and fix issues quickly -> Option B

4. Quick Check:

   Sysadmin skills = keep servers healthy [OK]

Hint: Sysadmin = server health and quick fixes [OK]

Common Mistakes:

• Confusing sysadmin with unrelated jobs
• Thinking sysadmin only writes code
• Ignoring server uptime importance

2. Which command is commonly used by sysadmins to check running processes on a Linux server?

easy

A. ps aux

B. ls -l

C. mkdir newfolder

D. cat /etc/passwd

Solution

1. Step 1: Identify commands related to process management

   Commands like 'ps aux' show running processes; others do different tasks.

2. Step 2: Match command to checking processes

   'ps aux' lists all running processes with details, useful for sysadmins.

3. Final Answer:

   ps aux -> Option A

4. Quick Check:

   Check processes = ps aux [OK]

Hint: Use 'ps aux' to see all running processes [OK]

Common Mistakes:

• Using 'ls -l' which lists files, not processes
• Confusing 'mkdir' with process commands
• Thinking 'cat /etc/passwd' shows processes

3. What will be the output of the command uptime on a production server?

medium

A. Shows current time, server uptime, and load averages

B. Deletes all files in the current directory

C. Displays disk usage statistics

D. Lists all users currently logged in

Solution

1. Step 1: Understand the purpose of 'uptime'

   The 'uptime' command shows how long the server has been running and system load.

2. Step 2: Identify correct output description

   It displays current time, uptime duration, and load averages, not file deletion or disk usage.

3. Final Answer:

   Shows current time, server uptime, and load averages -> Option A

4. Quick Check:

   uptime = server running time info [OK]

Hint: 'uptime' shows how long server runs [OK]

Common Mistakes:

• Confusing 'uptime' with file or disk commands
• Expecting it to list users or delete files
• Mixing it with 'df' or 'who' commands

4. A sysadmin runs the command systemctl start apache2 but gets an error. What is the most likely cause?

medium

A. The apache2 service is already running

B. The server is out of disk space

C. The user does not have permission to start services

D. The command syntax is incorrect

Solution

1. Step 1: Analyze the command and error context

   'systemctl start apache2' starts the web server service; error often means permission issue.

2. Step 2: Check common causes for failure

   Without root or sudo rights, starting services fails; syntax is correct and disk space unrelated here.

3. Final Answer:

   The user does not have permission to start services -> Option C

4. Quick Check:

   Permission error = no rights to start service [OK]

Hint: Starting services needs root or sudo rights [OK]

Common Mistakes:

• Assuming service is already running causes error
• Blaming syntax when command is correct
• Thinking disk space causes start failure

5. A sysadmin wants to automate daily backups on a production server. Which approach best uses sysadmin skills?

hard

A. Manually copy files every day at noon

B. Restart the server daily to clear memory

C. Use a text editor to write notes about backups

D. Write a shell script and schedule it with cron

Solution

1. Step 1: Identify automation methods for backups

   Automating backups requires scripting and scheduling tools like cron.

2. Step 2: Evaluate options for efficiency and reliability

   Manual copying is error-prone; notes or restarting server do not automate backups.

3. Final Answer:

   Write a shell script and schedule it with cron -> Option D

4. Quick Check:

   Automate backups = script + cron [OK]

Hint: Use scripts and cron for automation [OK]

Common Mistakes:

• Thinking manual copying is automation
• Confusing notes with actual backup
• Restarting server does not backup data