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A Cloud Guru

Working with Links in Linux

Understanding how soft and hard links work within Linux is another important skill for a system administrator. This learning activity will help you practice creating these two types of links on a file system, and explore the differences between the two.

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Path Info

Level

Beginner

Duration

30m

Published

Feb 12, 2019

Challenge

Create a Symbolic (soft) Link
Using the ln command, create a symbolic link from the file /etc/redhat-release to a new link file named release in the cloud_user's home directory. Using the ls command, verify that the link is valid. Use the cat command on the /home/cloud_user/release file to verify its contents.

Can be completed with:
```
ln -s /etc/redhat-release release
```
```
ls -l
```
```
cat /etc/redhat-release
```
Challenge

Check the Inode Numbers for the Link
Using the ls command, first look at the inode number for the /home/cloud_user/release link and then check the inode number for /etc/redhat-release. They should be different, as the symbolic link is just a new file system entry that references the original file.

Viewing the inodes can be done via:
```
ls -i release
```
```
ls -i /etc/redhat-release
```
Challenge

Create a Hard Link
Create a directory called docs in your home directory. Copy the /etc/services file into this new docs directory. Using the ln command again, create a hard link from /home/cloud_user/docs/services to a link file named /home/cloud_user/services. Use the ls command to verify the link's inode number, and the inode number for the original /etc/services file.

The commands to accomplish this task are:
```
mkdir docs
```
```
cp /etc/services docs/
```
```
ln docs/services services
```
```
ls -l
```
```
ls -i services
```
```
ls -i docs/services
```
Challenge

Attempt to Create a Hard Link Across File Systems
Using the ln command, attempt to make a hard link from /home/cloud_user/docs/services to /opt/services (you will have write permissions to this location). Why does this not work?

To see the behavior of this task, try the following:
```
lsblk 
```
```
ln docs/services /opt/services
```
Challenge

Attempt to Create a Symbolic Link Across File Systems
Once more using the ln command, attempt to create a soft link from /etc/redhat-release to /opt/release. Why does this work, but creating a hard link fails? Turn the system over for grading when complete.

Creating the soft link should succeed, even across filesystems, like so:
```
sudo ln -s /etc/redhat-release /opt/release
```
```
ls -i /etc/redhat-release
```
```
ls -i /opt/release
```

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

What's a lab?

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.