This is my TryHackMe walkthrough, created to document my learning journey and share solutions with the community. The writeups include a mix of hints, step-by-step explanations, and final answers to help players who get stuck, while still encouraging independent problem-solving.

Linux Modules Room - Learn linux modules in a fun way.

Overview

Learning Objectives

  • Key skills learned in this room:
    • Common commands to use in Linux: du, grep, tr, …
    • Linux based thinking

Walkthrough (Hints & Notes)

1. Let’s Introduce

No hints needed.

2. du

No hints needed.

3. Grep, Egrep, Fgrep

  • What user did you find in that file?
grep -i "user" grep_1611752025618.txt

uxx6x84XZw5VsQTHzVMN7F6fuxx6x84XZw5VsQTHzVMN7F6fuxx6x84XZw5VsQTHzVMN7F6fuxx6x84XZw5VsQTHzVMN7FuSeR:bobthebuilder6fuxx6x84XZw5VsQTHzVMN7F6fuxx6x84XZw5VsQTHzVMN7F6fuxx6x84XZw5VsQTHzVMN7F6f

=> Answer: bobthebuilder

  • What is the password of that user?
grep "sen" grep_1611752025618.txt

qEqbDkrSFzmhRdDSQNWqaMTXqEqbDkrSFzmhRdDSQNWqaMTthispAsSwOrDistoosensitive:'LinuxIsGawd'XqEqbDkrSFzmhRdDSQNWqaMTXqEqbDkrSFzmhRdDSQNWqaMTXqEqbDkrSFzmhRdDSQNWqaMTXqEqbDkrSFzmhRdDSQNWqaMTXqEqbDkrSFzmhRdDSQNWqaMTX

=> Answer: LinuxIsGawd

  • Can you find the comment that user just left?
grep "comment" grep_1611752025618.txt

8gmdNXTN4gn2u73SuX5cewcM8gmdNXTN4gn2comment:'fs0ciety'u73SuX5cewcM8gmdNXTN4gn2u73SuX5cewcM8gmdNXTN4gn2u73SuX5cewcM8gmdNXTN4gn2u73SuX5cewcM8gmdNXTN4gn2u73SuX5cewcM8gmdNXTN4gn2u73SuX5cewcM

=> Answer: fs0ciety

4. Did someone said STROPS?

No hints needed.

5. tr

  • Run tr –help command and tell how will you select any digit character in the string?

=> Answer: :digit:

  • What sequence is equivalent to [a-zA-Z] set?

=> Answer: :alpha:

  • What sequence is equivalent to selecting hexadecimal characters?

=> Answer: :xdigit:

6. awk

  • Download the above given file awk.txt, and use the awk command to print the following output:
ippsec:34024
john:50024
thecybermentor:25923
liveoverflow:45345
nahamsec:12365
stok:1234

=> Answer: awk 'BEGIN{OFS=":"} {print $1, $4}' awk.txt

  • How will you make the output as following (there can be multiple; answer it using the above specified variables in BEGIN pattern):
ippsec, john, thecybermentor, liveoverflow, nahamsec, stok,

=> Answer: awk 'BEGIN{ORS=","} {print $1}' awk.txt

7. sed

  • How would you substitute every 3rd occurrence of the word ‘hack’ to ‘back’ on every line inside the file file.txt?

=> Answer: sed 's/hack/back/3g' file.txt

  • How will you do the same operation only on 3rd and 4th line in file.txt?

=> Answer: sed '3,4 s/hack/back/3g' file.txt

  • Download the given file, and try formatting the trailing spaces in sed1.txt with a colon(:).

=> Answer: sed 's/ */:/g' sed1.txt

  • View the sed2 file in the directory. Try putting all alphabetical values together, to get the answer for this question.

=> Answer: CONGRATULATIONS YOU MADE IT THROUGH THIS SMALL LITTLE CHALLENGE

  • What pattern did you use to reach that answer string?

=> Answer: 's/[[:digit:]]//g'

  • What did she sed?(In double quotes)

=> Answer: "That's What"

8. xargs

  • You’re working in a team and your team leader sent you a list of files that needs to be created ASAP within current directory so that he can fake the synopsis report (that needs to be submitted within a minute or 2) to the invigilator and change the permissions to read-only to only you(Numberic representation). You can find the files list in the “one” folder.

  • Use the following flags in ASCII order:

    • Verbose
    • Take argument as “files”

=> Answer: cat file | xargs -I files -t sh -c “touch files; chmod 400 files”

  • Your friend trying to run multiple commands in one line, and wanting to create a short version of rockyou.txt, messed up by creating files instead of redirecting the output into “shortrockyou”. Now he messed up his home directory by creating a ton of files. He deleted rockyou wordlist in that one liner and can’t seem to download it and do all that long process again.

  • He now seeks help from you, to create the wordlist and remove those extra files in his directory. You being a pro in linux, show him how it’s done in one liner way.

  • Use the following flags in ASCII order:

    • Take argument as “word”
    • Verbose
    • Max number of arguments should be 1 in for each file

  • You can find the files for this task in two folder.

=> Answer: ls | xargs -I word -n 1 -t sh -c ‘echo word >> shortrockyou; rm word’

  • Which flag to use to specify max number of arguments in one line.

=> Answer: -n

  • How will you escape command line flags to positional arguments?

=> Answer: --

9. sort and uniq

  • Download the file given for this task, find the uniq items after sorting the file. What is the 2271st word in the output.
sort test_1611747033664.test | uniq | sed -n '2270p'

=> Answer: lollol

  • What was the index of term ‘michele’
sort test_1611747033664.test| grep -n "michele"

=> Answer: 2550

10. cURL

  • Which flag allows you to limit the download/upload rate of a file?

=> Answer: --limit-rate

=> Answer: curl -A "juzztesting" https://tryhackme.com/

  • Can curl perform upload operations?(Yea/Nah)

=> Answer: Yea

11. wget

  • How will you enable time logging at every new activity that this tool initiates?

=> Answer: -N

=> Answer: wget -a package-logs.txt https://xyz.com/mypackage.zip

  • Write the command to read URLs from “file.txt” and limit the download speed to 1mbps.

=> Answer: wget -i file.txt --limit-rate=1m

12. xxd

  • How will you seek at 10th byte(in hex) in file.txt and display only 50 bytes?

=> Answer: xxd -s 0xa -l 50 -b file.txt

  • How to display a n bytes of hexdump in 3 columns with a group of 3 octets per row from file.txt? (Use flags alphabetically)

=> Answer: xxd -c 9 -g 3 file.txt

  • Which has more precedence over the other -c flag or -g flag?

=> Answer: -c

  • Download the file and find the value of flag.
echo "666c61677b776833736477306c7731676c396f7161736164326673343861737d0a" | xxd -r -p

=> Answer: flag{wh3sdw0lw1gl9oqasad2fs48as}

13. Other modules

  • It’s safe to run systemctl command and experiment on your main linux system neither following a proper guide or having any prior knowledge? (Right/Wrong)

=> Answer: Wrong

  • How will you import a given PGP private key. (Suppose the name of the file is key.gpg)

=> Answer: gpg --import key.gpg

  • How will you list all port activity if netstat is not available on a machine? (Full Name)

=> Answer: Socket Statistics

  • What command can be used to fix a broken/irregular/weird acting terminal shell?

=> Answer: reset

14. Is it night yet?

  • Press F to pay respect

=> Answer: F