Linux readlink Command with Practical Examples

Introduction

In this lab, you will learn about the Linux readlink command and how to use it to work with symbolic links. The lab covers the purpose of the readlink command, its syntax and available options, and provides practical examples of resolving symbolic links. This knowledge can be helpful when working with files and directories that are referenced by symbolic links, as the readlink command allows you to determine the actual path of the target. The content of this lab is focused on the basic file and directory operations in Linux.

Linux Commands Cheat Sheet

Skills Graph

Understand the Purpose of the readlink Command

In this step, you will learn about the purpose of the readlink command in Linux. The readlink command is used to display the value of a symbolic link. It is a useful tool for resolving the actual path of a symbolic link, which can be helpful when working with files and directories.

To begin, let's create a symbolic link in the ~/project directory:

cd ~/project
ln -s /usr/bin/python3 python_link

Now, let's use the readlink command to display the value of the symbolic link:

readlink python_link

Example output:

/usr/bin/python3

As you can see, the readlink command displays the actual path that the symbolic link python_link points to, which is /usr/bin/python3.

The readlink command can be particularly useful when you need to know the real path of a file or directory that is referenced by a symbolic link. This can be helpful when working with scripts or applications that rely on specific file paths.

Explore the Syntax and Options of the readlink Command

In this step, you will explore the syntax and available options of the readlink command.

The basic syntax of the readlink command is:

readlink [options] file

Here are some common options for the readlink command:

• -f: Follows all symbolic links and returns the final target of the link.
• -e: Exits with an error if the file does not exist or is not a symbolic link.
• -n: Omits the trailing newline character from the output.
• -m: Prints the canonical path, handling both symbolic and hard links.

Let's try out some of these options:

## Follow the symbolic link and print the final target
readlink -f python_link

## Print the canonical path, handling both symbolic and hard links
readlink -m python_link

## Omit the trailing newline character
readlink -n python_link

Example output:

/usr/bin/python3
/usr/bin/python3
/usr/bin/python3

As you can see, the readlink command provides various options to customize the output and behavior when working with symbolic links.

Practice Resolving Symbolic Links with the readlink Command

In this final step, you will practice resolving symbolic links using the readlink command.

First, let's create a few more symbolic links in the ~/project directory:

cd ~/project
ln -s /bin/ls ls_link
ln -s ls_link nested_link

Now, let's use the readlink command to resolve the paths of these symbolic links:

readlink ls_link
readlink nested_link

Example output:

/bin/ls
ls_link

As you can see, the readlink command displays the actual path that the ls_link symbolic link points to, which is /bin/ls. For the nested_link symbolic link, readlink shows that it points to the ls_link symbolic link.

To follow the chain of symbolic links and get the final target, you can use the -f option:

readlink -f nested_link

Example output:

/bin/ls

The -f option follows all symbolic links and returns the final target of the link chain.

Try practicing with these symbolic links and the readlink command to become more familiar with resolving symbolic links in Linux.

Summary

In this lab, you first learned about the purpose of the readlink command in Linux, which is used to display the value of a symbolic link. You created a symbolic link and used readlink to display the actual path that the link points to. Then, you explored the syntax and available options of the readlink command, such as -f to follow all symbolic links, -e to exit with an error if the file is not a symbolic link, -n to omit the trailing newline character, and -m to print the canonical path. By understanding the readlink command and its various options, you can effectively work with symbolic links and resolve the actual paths of files and directories in your Linux environment.

Linux Commands Cheat Sheet