Navigation in Linux with Examples

By Ravindra Bagale Last updated: 15 October 2026

Come on, let's try it now. Log in to any Linux machine (or your EC2 instance) and type these commands with me.

Command	Meaning	Example
`pwd`	Print working (current) directory	`pwd` → `/home/ubuntu`
`ls`	List files	`ls`, `ls -l`, `ls -la`, `ls -lh /var/log`
`cd`	Change directory	`cd /etc`, `cd ..`, `cd ~`, `cd -`
`tree`	Show folder tree (install package `tree`)	`tree -L 2 /etc/nginx`
`clear`	Clear the screen (or press Ctrl+L)
`history`	Previous commands	`history \| tail -20`, then `!45` to re-run no. 45

pwd                 # where am I?
ls -la              # long listing including hidden files (starting with .)
cd /var/log         # absolute path (starts with /)
cd ../www           # relative path (.. = parent, . = current)
cd ~                # go to home directory (same as just 'cd')
cd -                # go back to the previous directory

Understanding ls -l output:

-rw-r--r--  1 ec2-user ec2-user  1024 Mar  3 10:15 notes.txt
│└──┬───┘   │ └──┬───┘ └──┬───┘  └┬─┘ └─────┬────┘ └───┬───┘
│ permissions links owner  group   size  modified time   name
└─ type: - file, d directory, l symbolic link

Keyboard shortcuts that save hours

Tab auto-completes file and command names (press twice to see options). ↑ / ↓ scroll through history. Ctrl+C stops a running command. Ctrl+R searches history. Ctrl+A / Ctrl+E jump to start / end of line.

Ravindra Bagale's Tip

Many students type every path fully by hand and get the spelling wrong. Press Tab and Linux completes the name itself – and if Tab gives nothing, the path is wrong. Use cd - to go back to the previous folder, and always check "where am I" with pwd.

Ravindra Bagale's Tip – मराठी

बरेच students प्रत्येक path पूर्ण हाताने type करतात आणि spelling चुकवतात. Tab दाबला की Linux स्वतः नाव पूर्ण करतो – आणि Tab ने काहीच आलं नाही तर path चुकीचा आहे. cd - ने मागच्या folder मध्ये परत जा, आणि pwd ने नेहमी "मी कुठे आहे" हे check करा.

Ravindra Bagale's Tip – हिंदी

बहुत से students हर path पूरा हाथ से type करते हैं और spelling गलत कर देते हैं. Tab दबाओ तो Linux ख़ुद नाम पूरा करता है – और Tab से कुछ नहीं आया तो path गलत है. cd - से पिछले folder में वापस जाओ, और pwd से हमेशा "मैं कहाँ हूँ" check करो.

Lab

Chala, cd /var/log kara, ls -lh chalva aani sagalyat mothi file konti te shodha. Mag cd - ne parat ya, history | tail -5 bagha aani ! sobat number vaprun ek juni command parat chalva.

Extended teaching notes

Why this lesson matters

Cloud security is mostly IAM, network exposure, logging and secure defaults. The shared responsibility model means the provider patches the metal; you patch what you configure.

No public databases or public admin panels.
Roles / OIDC instead of long-lived access keys.
CloudTrail / Activity Logs / Audit Logs on and retained.
S3/Blob/GCS: Block Public Access; encrypt; least privilege.

Mini case study

Suppose we are on a purple-team exercise for an Indian mid-size company (sample data). Red notes a technique from this lesson against a lab clone. Blue must show the control that stops it, the log that would have fired, and the ticket that hardens production. That is the standard this course trains you for.

Defender's worksheet (do this today)

Write the lesson title, date and the exact lab target you are allowed to use.
List three owned systems (VMs, apps, or cloud accounts) where this lesson applies.
Run one safe check from the lesson on a lab system only. Paste the command and output.
Write a two-sentence fix you would give a teammate.
Name one related public advisory (CERT-In, CISA, NVD, or a vendor bulletin) with its date.

Indian workplace (sample data)

Suppose we are a junior analyst at Infosys, TCS, Wipro or a fintech SOC in Bengaluru/Pune. Turn this lesson into one checklist item with an owner, a due date and a place to store evidence (ticket + screenshot).

Global practice

Compare your notes with OWASP, CIS Benchmarks, NIST CSF/IR guidance or a cloud Well-Architected security question. Write five lines on what overlaps.

Everyday analogy

Explain the risk and the fix to a family member without jargon. If they can repeat the warning, you understand it well enough to teach juniors.

Key terms

Control: a safeguard (patch, config, process, detection).
Finding: a weakness backed by evidence.
Remediation: the fix plus how you verified it.
Scope: systems you have written permission to touch.
Least privilege: only the access the task needs.
Defence in depth: several layers so one failure does not end the story.

Common mistakes

Skipping written permission "just for a quick scan".
Practising on hostel, office or public targets without authorisation.
Collecting tool output without writing the fix.
Copying attack steps onto production to "verify". Defenders verify with versions, configs and patches.
Publishing screenshots that contain secrets, cookies or internal hostnames.

Recap

Evidence, fix, owner, date.
Own lab only.
Fix > spectacle.