Lab
A Cloud Guru

Using File Attributes and Permissions

Both file attributes and permissions determine user and group access to files throughout the file system. Therefore, being able to use file attributes and permissions effectively is an essential system administrator skill. In this Hands-On lab, you will be using commands to view and set permissions and attributes for files. When the lab is complete, you should know how to use file attributes and permissions to control user and group access to files in the file system.

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Path Info

Level

Beginner

Duration

15m

Published

Jan 17, 2020

Challenge

View the Current Permissions of /opt/myapp/start.sh
Let's see where we stand, as far as permissions go. Run ls -l and stat on the /opt/myapp/start.sh file:
```
cd /opt/myapp
ls -l start.sh
stat start.sh
```
Challenge

Change Permissions on /opt/myapp/start.sh to Allow Full Privileges for User and Group Only
Currently, the permissions of the file /opt/myapp/start.sh are rw-r--r--, or mode 644. We need the user and group to have all permissions and the others to have none. Using either command will have the same result:
```
ls -l start.sh
chmod u=rwx,g+wx,o-r start.sh
ls -l start.sh
stat start.sh
chmod 770 start.sh
stat start.sh
```
Challenge

Verify That /opt/myapp/start.sh Is Executable
The permissions of the file /opt/myapp/start.sh should now be -rwxrwx--- or mode 770, and the file should execute. Look at the permissions again to make sure:
```
stat start.sh
```
Now let's try running it:
```
./start.sh
```
Challenge

Make the /opt/myapp/start.sh Immutable Using a File Attribute
The i attribute should appear when we run lsattr on the file:
```
lsattr start.sh
```
If it doesn't, then we've got to set it:
```
sudo chattr +i start.sh
```
Verify that the file is set immutable:
```
lsattr start.sh
```
Note the use of sudo there. We've got to run chattr as root.

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.