The cd command in Ubuntu (and other Linux distributions) stands for "change directory." It allows you to navigate between directories in the file system, making it an essential command for moving around within the structure of files and directories.

Syntax

cd [directory_path]

If no path is provided, cd takes you to your home directory by default.

1. Basic Usage of cd

Navigate to a Specific Directory

To move into a specific directory, type cd followed by the path to that directory:

cd /path/to/directory

For example:

cd /home/user/Documents

This command takes you to the Documents folder inside the /home/user directory.

Go to the Home Directory

Simply typing cd with no arguments returns you to your home directory:

cd

Alternatively, you can use:

cd ~

Move Up One Directory Level

To go up one level from the current directory, use .. after cd:

cd ..

For example, if you’re in /home/user/Documents and type cd .., you’ll move up one level to /home/user.

Move to the Previous Directory

To switch back to the previous directory you were in, use:

cd -

This is helpful when you’re working between two directories.

2. Absolute vs. Relative Paths

• Absolute Path: A full path that starts from the root directory (/). This path is fixed and independent of the current directory.

  cd /home/user/Documents
  

• Relative Path: A path relative to the current directory. This is useful when you’re navigating to a subdirectory or moving up levels.

  cd Documents     # If you're in /home/user, this goes to /home/user/Documents
  cd ../Pictures   # Moves up one level, then into Pictures
  

3. Special Symbols with cd

• Home Directory (~): The tilde (~) represents the home directory.

  cd ~
  

• Parent Directory (..): The double dots (..) represent the parent directory, allowing you to go up one level.

  cd ..
  

• Current Directory (.): A single dot (.) represents the current directory, though it’s rarely used with cd.

  cd .
  

4. Examples of cd in Action

• Navigate to the Desktop folder in your home directory:

  cd ~/Desktop
  

• Move to the root directory:

  cd /
  

• Navigate back to the previous directory:

  cd -
  

5. Using cd with Auto-completion

When typing a directory path, press Tab after typing part of a directory name. The terminal will auto-complete the name if it’s unique or show options if there are multiple matches. This is useful for faster navigation and avoiding typos.

Summary

The cd command is essential for navigating directories in Ubuntu. Using cd with absolute and relative paths, and combining it with shortcuts like .. and ~, provides a quick way to control your location within the file system. This command is fundamental for efficient file and directory management in any Linux environment.