Scenario: "Saskatoon": counting IPs.

Level: Easy

Type: Do

Access: Email

Description: There's a web server access log file at /home/admin/access.log. The file consists of one line per HTTP request, with the requester's IP address at the beginning of each line.

Find what's the IP address that has the most requests in this file (there's no tie; the IP is unique). Write the solution into a file /home/admin/highestip.txt. For example, if your solution is "1.2.3.4", you can do echo "1.2.3.4" > /home/admin/highestip.txt

Test: The SHA1 checksum of the IP address sha1sum /home/admin/highestip.txt is 6ef426c40652babc0d081d438b9f353709008e93 (just a way to verify the solution without giving it away.)

Time to Solve: 15 minutes.

Scenario: "The Command Line Murders"

Level: Easy

Type: Do

Access: Public

Description: This is the Command Line Murders with a small twist as in the solution is different

Enter the name of the murderer in the file /home/admin/mysolution, for example echo "John Smith" > ~/mysolution

Hints are at the base of the /home/admin/clmystery directory. Enjoy the investigation!

Test: md5sum ~/mysolution returns 9bba101c7369f49ca890ea96aa242dd5

(You can always see /home/admin/agent/check.sh to see how the solution is evaluated).

Time to Solve: 20 minutes.

Scenario: "Lhasa": Easy Math

Level: Easy

Type: Do

Access: Email

Description: There's a file /home/admin/scores.txt with two columns (imagine the first number is a counter and the second one is a test score for example).

Find the average (more precisely; the arithmetic mean: sum of numbers divided by how many numbers are there) of the numbers in the second column (find the average score).

Use exactly two digits to the right of the decimal point. i. e., use exaclty two "decimal digits" without any rounding. Eg: if average = 21.349 , the solution is 21.34. If average = 33.1 , the solution is 33.10.

Save the solution in the /home/admin/solution file, for example: echo "123.45" > ~/solution

Tip: There's bc, Python3, Golang and sqlite3 installed in this VM.

Test: md5sum /home/admin/solution returns 6d4832eb963012f6d8a71a60fac77168 solution

Time to Solve: 15 minutes.

Scenario: "Bata": Find in /proc

Level: Easy

Type: Do

Access: Email

Description: A spy has left a password in a file in /proc/sys . The contents of the file start with "secret:" (without the quotes).

Find the file and save the word after "secret:" to the file /home/admin/secret.txt with a newline at the end (e.g. if the file contents were "secret:password" do: echo "password" > /home/admin/secret.txt).

(Note there's no root/sudo access in this scenario).

Test: Running md5sum /home/admin/secret.txt returns a7fcfd21da428dd7d4c5bb4c2e2207c4

The "Check My Solution" button runs the script /home/admin/agent/check.sh, which you can see and execute.

Time to Solve: 10 minutes.

Scenario: "Oaxaca": Close an Open File

Level: Medium

Type: Fix

Access: Email

Description: The file /home/admin/somefile is open for writing by some process. Close this file without killing the process.

Test: lsof /home/admin/somefile returns nothing.

Time to Solve: 15 minutes.

Scenario: "Marrakech": Word Histogram

Level: Medium

Type: Do

Access: Email

Description: Find in the file frankestein.txt the second most frequent word and save in UPPER (capital) case in the /home/admin/mysolution file.

A word is a string of characters separated by space or newlines or punctuation symbols .,:; . Disregard case ('The', 'the' and 'THE' is the same word) and for simplification consider the apostrophe as another character not as punctuation ("it's" would be a word, distinct from "it" and "is"). Also disregard plurals ("car" and "cars" are different words) and other word variations (don't do "stemming").

We are providing a shorter test.txt file where the second most common word in upper case is "WORLD", so we could save this solution as: echo "WORLD" > /home/admin/mysolution

This problem can be done with a programming language (Python, Golang and sqlite3) or with common Linux utilities.

Test: echo "SOLUTION" | md5sum returns 19bf32b8725ec794d434280902d78e18

See /home/admin/agent/check.sh for the test that "Check My Solution" runs.

Time to Solve: 20 minutes.

Scenario: "Hanoi": Find the Multitasking Users

Level: Medium

Type: Do

Access: Paid

Description: The Hanoi office has a Linux server with a large number of user accounts and groups. The system administrators need to identify which users belong to multiple groups for better access management.

Given two files, `users.txt` and `groups.txt`, create a new file `/home/admin/multi-group-users.txt` containing the usernames of users who belong to more than one group, one username per line, sorted alphabetically.

The `users.txt` file contains a list of usernames, one per line. The `groups.txt` file contains group names and their members, in the format `group_name:user1,user2,user3`.

Test: Running md5sum /home/admin/multi-group-users.txt returns dc0ae86caae7125d21df03a0ab29d8ae

The "Check My Solution" button runs the script /home/admin/agent/check.sh, which you can see and execute.

Time to Solve: 15 minutes.