2.2 Files and Directories

Understanding Files and Directories on Linux

On Linux, almost everything is represented as a file, and files are organized into a tree of directories (folders). This chapter gives you the practical basics you need at the command line; later chapters will go deeper into searching, permissions, and special filesystem locations.

The Filesystem as a Tree

The Linux filesystem is structured like an upside‑down tree:

The top of the tree is the root directory: /
Directories can contain:

Regular files
Other directories (subdirectories)
Other special file types (covered elsewhere)

A path is how you describe where a file or directory lives in this tree:

/home/alice/Documents/notes.txt is a path
Each / separates directory levels
The last component is usually the file name (notes.txt)

You’ll use paths constantly with command‑line tools.

Your Current Location: Working Directory

When you open a terminal, you are “inside” a directory. This is your current working directory.

pwd — print working directory:

  pwd
  /home/alice

cd — change directory:

  cd /home/alice/Documents
  pwd
  /home/alice/Documents

You can only refer to relative paths (e.g. Documents/report.txt) if you know what your current directory is; otherwise you must use absolute paths that start with / (covered more later).

Basic Path Components: `.` and `..`

Two special directory names exist everywhere:

. — the current directory
.. — the parent directory (one level up)

These are just names you can use in commands:

# Go to the parent directory
cd ..
# Refer to a file in the current directory explicitly
ls ./file.txt
# Go up one directory, then into another
cd ../Downloads

Viewing Directory Contents with `ls`

The main tool to see what’s in a directory is ls.

Simple listing

ls
Desktop  Documents  Downloads  Pictures

If no directory is given, ls lists the current directory.

You can list a specific path:

ls /etc

Long listing

ls -l shows more detail:

ls -l
total 8
drwxr-xr-x 2 alice alice 4096 Dec  1 10:20 Documents
-rw-r--r-- 1 alice alice  123 Nov 30 09:15 todo.txt

You’ll learn what each column means in the permissions chapter, but for now:

Entries starting with d are directories
Entries starting with - are regular files

Showing hidden files

On Linux, a hidden file is any file whose name starts with a dot (.), e.g. .bashrc.

To see them:

ls -a
.  ..  .bashrc  Documents  todo.txt

Combine options:

ls -la

Navigating Directories with `cd`

cd changes your current working directory.

Common usages:

Go to your home directory (e.g. /home/alice):

  cd
  # or
  cd ~

Go to a specific absolute path:

  cd /var/log

Go to a path relative to where you are:

  cd Documents
  cd ../Pictures

Go to the previous directory:

  cd -

This toggles between the current directory and the one you were in before.

Paths: Absolute vs Relative

You will use two kinds of paths with most commands:

Absolute path

Starts with /
Always describes the same location, no matter where you are
Example: /home/alice/Documents/report.txt

Relative path

Does not start with /
Interpreted relative to your current working directory
Example: if you are in /home/alice, then:

Documents/report.txt means /home/alice/Documents/report.txt
../bob/notes.txt means /home/bob/notes.txt

You can always convert “Where am I + relative path” to an absolute path:

If pwd prints /home/alice and you run:

ls Documents/report.txt

The shell effectively interprets it as:

ls /home/alice/Documents/report.txt

Creating Directories: `mkdir`

To create new directories:

Single directory:

  mkdir projects
  ls
  projects

Nested directories (parents created automatically):

  mkdir -p projects/2025/january

Without -p, mkdir projects/2025/january would fail if projects or 2025 don’t exist.

You can create multiple directories at once:

mkdir dir1 dir2 dir3

Creating and Copying Files and Directories

Creating empty files with `touch`

touch updates timestamps on files, and if the file does not exist, it creates an empty one:

touch notes.txt
ls
notes.txt

You can create several:

touch file1.txt file2.txt file3.txt

Copying files with `cp`

Basic usage:

cp source_file destination_file

Examples:

Copy a file in the same directory:

  cp notes.txt notes_backup.txt

Copy a file to another directory:

  cp notes.txt Documents/

To copy a directory and its contents, use -r (recursive):

cp -r projects/ projects_backup/

It’s common to use -v (verbose) to see what’s happening:

cp -rv projects/ projects_backup/

Moving and Renaming with `mv`

mv moves files/directories and also renames them.

Rename a file in the same directory:

  mv notes.txt ideas.txt

Move a file to another directory:

  mv ideas.txt Documents/

Move and rename at once:

  mv Documents/ideas.txt Documents/old_ideas.txt

Move a directory:

  mv projects/ /home/alice/old_projects/

Removing Files and Directories with `rm` and `rmdir`

Removing is permanent at the command line; there is no recycle bin.

Removing files with `rm`

Remove a single file:

  rm notes.txt

Remove multiple files:

  rm file1.txt file2.txt

Ask for confirmation before each file:

  rm -i *.txt

Removing directories

Empty directories:

rmdir emptydir

Directories and their contents (recursive):

rm -r projects_backup/

Be very careful with:

rm -r — removes directories recursively
rm -rf — same as above but forces removal, skipping confirmation and errors

A common safe habit while learning:

Use rm -ri instead of rm -r so you get prompted.

Paths with `~` (Home Directory Shortcut)

~ is a shortcut for your user’s home directory:

On most systems: /home/yourusername
On some systems: /Users/yourusername or /home/yourusername (concept is the same)

Examples:

cd ~           # go to your home
ls ~/Documents # list Documents in your home
cp file.txt ~/Downloads/

In shells like Bash, ~username refers to another user’s home (if you have permission):

ls ~bob

Inspecting Paths and File Locations

Sometimes you want to know where exactly something is or what kind of file a path refers to.

Showing the full path with `realpath` or `readlink -f`

If available on your system:

realpath Documents/report.txt
# or
readlink -f Documents/report.txt

These commands resolve relative paths to absolute ones.

File type and basic info with `file`

To see what type of data a file contains (text, binary, image, etc.):

file notes.txt
# notes.txt: ASCII text
file /bin/ls
# /bin/ls: ELF 64-bit LSB pie executable, ...

Tab Completion for File and Directory Names

Most shells provide tab completion:

Type the first few letters of a file or directory name
Press Tab
The shell auto‑completes the rest if unambiguous

Example:

You have Documents and Downloads
Type cd Do + Tab:

The shell may expand to cd Doc and wait (because there are multiple matches)
Press Tab twice to see suggestions
Type more letters (Docu) and press Tab again

Tab completion saves time and prevents typos when working with long paths.

Basic Directory Organization Habits

Even as a beginner, a few simple habits make life easier:

Keep personal files under your home directory (e.g. ~/Documents, ~/Projects)
Avoid storing random work in system directories like /etc, /usr, /bin
Use descriptive names and consistent structure:

~/projects/linux-course/notes.txt
~/projects/linux-course/examples/

The tools in this chapter (ls, cd, mkdir, cp, mv, rm) are the foundation. Later chapters will build on these to search, manage permissions, and work with more advanced file operations.

2.2.1 Listing files

2.2.2 Navigating directories

2.2.3 File operations

2.2.4 Wildcards and globbing

2.2.5 Searching files

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