Navigation¶

Moving around the filesystem efficiently is fundamental to command-line productivity.

The Filesystem Hierarchy¶

Unix filesystems are organized as a tree starting from root (/):

/
├── bin/          # Essential binaries
├── etc/          # System configuration
├── home/         # User home directories (Linux)
├── Users/        # User home directories (macOS)
├── tmp/          # Temporary files
├── usr/          # User programs and data
│   ├── bin/      # User binaries
│   ├── local/    # Locally installed software
│   └── share/    # Shared data
└── var/          # Variable data (logs, etc.)

Print Working Directory (pwd)¶

Always know where you are:

pwd

/Users/username/projects

Change Directory (cd)¶

Move to a different directory:

cd /etc           # Absolute path
cd projects       # Relative path
cd                # Go to home directory
cd ~              # Also home directory
cd -              # Previous directory
cd ..             # Parent directory
cd ../..          # Two levels up

Home Directory Shortcuts¶

cd                # Home
cd ~              # Home
cd ~/Documents    # Documents in home
cd ~username      # Another user's home

Previous Directory¶

The - shortcut toggles between last two directories:

cd /var/log
pwd

/var/log

cd /etc
pwd

/etc

cd -
pwd

/var/log

Absolute vs Relative Paths¶

Absolute paths start from root (/):

cd /home/username/projects
cd /etc/nginx

Relative paths start from current directory:

cd projects          # Same as ./projects
cd ./projects        # Explicit relative
cd ../sibling        # Up one, then into sibling

Special Directory References¶

Symbol	Meaning
`/`	Root directory
`~`	Home directory
`.`	Current directory
`..`	Parent directory
`-`	Previous directory (cd only)

Directory Stack (pushd/popd)¶

When working across multiple directories, the directory stack helps you jump back:

pushd - Push and Change¶

pwd

/home/user

pushd /var/log

/var/log /home/user

pushd /etc

/etc /var/log /home/user

The stack shows most recent first.

popd - Pop and Return¶

popd

/var/log /home/user

pwd

/var/log

dirs - View Stack¶

dirs

/var/log /home/user

With line numbers:

dirs -v

 0  /var/log
 1  /home/user

Jump to Stack Position¶

pushd +1    # Jump to position 1
pushd -0    # Jump to last position

Clear the Stack¶

dirs -c

Tab Completion¶

Bash can complete paths when you press Tab:

cd /usr/lo<Tab>
# Completes to: cd /usr/local/

Double-tab shows options:

cd /usr/<Tab><Tab>
# Shows: bin/  include/  lib/  local/  share/

Wildcards in Paths¶

Navigate with glob patterns:

cd ~/Doc*           # Matches ~/Documents
cd /etc/ssh*        # First match starting with ssh

CDPATH Variable¶

Define directories to search when using cd:

export CDPATH=".:~:~/projects"

Now from anywhere:

cd myproject        # Finds ~/projects/myproject

CDPATH Caveat

CDPATH can cause confusion in scripts. Consider using it only interactively.

Quick Project Access¶

Add to your .bashrc:

# Quick project navigation
proj() {
    cd ~/projects/"$1" 2>/dev/null || echo "Project not found: $1"
}

Usage:

proj myapp

Bookmark Directories¶

# Save current directory
alias mark='pwd > ~/.marked_dir'

# Return to marked directory
alias back='cd "$(cat ~/.marked_dir)"'

Create and Enter Directory¶

mkcd() {
    mkdir -p "$1" && cd "$1"
}

Usage:

mkcd new-project

autojump / z / zoxide¶

These tools learn your habits and let you jump to frequent directories:

# After visiting ~/projects/myapp several times
z myapp             # Jumps to ~/projects/myapp

Install zoxide (recommended):

brew install zoxide

Add to .bashrc:

eval "$(zoxide init bash)"

Fuzzy find directories:

cd "$(find . -type d | fzf)"

Or with a function:

fcd() {
    local dir
    dir=$(find ${1:-.} -type d 2>/dev/null | fzf) && cd "$dir"
}

Common Mistakes¶

Spaces in Paths¶

Quote paths with spaces:

cd "My Documents"       # Correct
cd My\ Documents        # Also correct (escaped space)
cd My Documents         # Wrong - tries cd to "My"

Case Sensitivity¶

Linux is case-sensitive; macOS is case-insensitive by default:

# Linux
cd Documents    # Different from
cd documents    # This one

# macOS (default) - both work

Missing Directories¶

Check if directory exists before changing:

[[ -d /some/path ]] && cd /some/path || echo "Not found"

Try It¶

Practice basic navigation:
```
cd /var/log
pwd
cd ..
pwd
cd -
```

Use the directory stack:

pushd /etc
pushd /var
pushd /tmp
dirs -v
popd
popd
popd

Create the mkcd function and test it:

mkcd() { mkdir -p "$1" && cd "$1"; }
mkcd ~/test-navigation
pwd
cd ..
rm -r ~/test-navigation

Summary¶

Command	Purpose
`pwd`	Show current directory
`cd <path>`	Change directory
`cd` or `cd ~`	Go home
`cd -`	Previous directory
`cd ..`	Parent directory
`pushd <path>`	Push to stack and change
`popd`	Pop stack and return
`dirs`	Show directory stack