Navigate the filesystem with confidence

Goal

By the end of this lesson you will be able to move around any Linux server quickly, understand where you are, and find what you need without guessing.

This is not about memorizing commands. It is about building a mental model of paths.

Mental Model (2 minutes)

Think of the filesystem as a tree. Everything is a path.

/
├─ home/
│  └─ rahul/
│     ├─ projects/
│     └─ notes.txt
├─ etc/
├─ var/
└─ tmp/

You always have:

• a current directory (your location in the tree)
• a target path (where you want to go)

Core Commands You Must Know

1) Where am I?

pwd

Prints the full absolute path of your current directory.

2) What is here?

ls
ls -lah

Useful flags:

• -l: long listing (permissions, owner, size, time)
• -a: include hidden files (starting with .)
• -h: human sizes (K, M, G)

3) Move to another folder

cd /etc
cd ..
cd ~
cd -

Important shortcuts:

• . = current directory
• .. = parent directory
• ~ = your home directory
• cd - = jump back to the previous directory

Absolute vs Relative Paths (the most important concept)

Absolute path

Starts from root /.

Example:

cd /var/log

Relative path

Starts from where you currently are.

Example:

cd logs

This only works if a folder named logs exists inside your current directory.

Hidden Files (dotfiles)

Hidden files start with . (like .env, .git, .ssh).

ls -a

Common mistake: people think the file is missing, but it is hidden.

Reading a Directory Listing (like a DevOps engineer)

ls -l

The first character in permissions shows the type:

• - regular file
• d directory
• l symlink (shortcut)

If you see a symlink:

ls -l somefile
readlink -f somefile

Practical Navigation Patterns (what you do in real work)

Jump into logs and back fast

cd /var/log
ls -lah
cd -

Use tab completion (speed)

Start typing and press TAB:

cd /va<TAB>

Create a safe sandbox in /tmp

mkdir -p /tmp/devopslabx-lab
cd /tmp/devopslabx-lab

Finding Things (basic, but extremely useful)

Find by name (fast enough for most tasks)

find . -maxdepth 3 -name "*.log"
find /var/log -type f -name "*.log" 2>/dev/null

Find by content (logs, configs)

grep -R "ERROR" .
grep -R "listen" /etc/nginx 2>/dev/null

Exercises (do these)

Exercise A: Build your navigation muscle

1. Create folders:

mkdir -p lab/a/b/c

1. Move into c using a relative path.
2. Move back to lab using ...
3. Jump to your home directory.
4. Jump back using cd -.

Exercise B: Hidden files

1. Create a hidden file:

touch .secret

1. Confirm you cannot see it with ls.
2. Confirm you can see it with ls -a.

Exercise C: Find + grep

1. Create a file with a few lines containing the word deploy.
2. Use grep to find those lines.
3. Use find to locate that file by name.

Troubleshooting Checklist

If cd fails:

• did you type the path correctly (case matters)
• are you using relative path but you are in the wrong folder
• do you have permissions (try ls -ld <dir>)

If a file is missing:

• is it hidden (ls -a)
• is it a symlink to somewhere else (ls -l)

Quick Cheat Sheet

pwd                 # where am I?
ls -lah             # what's here (including hidden)
cd /path/to/dir     # go to absolute path
cd ..               # go up one level
cd ~                # home
cd -                # previous directory
find . -name "*.yml"   # search by name
grep -R "text" .       # search by content

Next Step

Once navigation feels easy, you are ready for permissions (chmod, chown) and services (systemctl) because you will always know where configs and logs live.