blkid: Locate and identify block devices

Mastering the blkid Command: Discover Block Devices on Your Linux System

When working with Linux, understanding and managing your storage devices effectively is crucial whether you're a system administrator, a developer, or a power user managing your personal system. The blkid command is a powerful tool designed for locating and identifying block devices such as hard drives, SSDs, and their partitions with critical information like UUIDs and filesystem types. This guide dives into the basics of blkid, its usage, and how to install it across various Linux distributions using different package managers.

What is blkid?

The blkid program is part of the util-linux package, which comes with numerous essential tools for system management. blkid provides you with the attributes of block devices installed on your system. These attributes include the universally unique identifier (UUID), type of filesystem, label, and more, which can be crucial for system maintenance and scripts that automate disk management tasks.

Installation Instructions

1. Debian/Ubuntu (using apt)

For systems based on Debian or Ubuntu, blkid is typically pre-installed as part of the util-linux package. However, if for some reason it is absent, you can install it by opening your terminal and running the following commands:

sudo apt update
sudo apt install util-linux

2. Fedora/RHEL/CentOS (using dnf)

On Fedora and other Red Hat-based systems like RHEL or CentOS, blkid also comes pre-installed. In case you need to ensure it is present or need to install any missing utilities from util-linux, use the following commands:

sudo dnf check-update
sudo dnf install util-linux

3. openSUSE (using zypper)

Similarly, for openSUSE users, blkid is available as part of the util-linux package. It can be installed or verified using zypper:

sudo zypper refresh
sudo zypper install util-linux

How to Use blkid

Once blkid is installed, you can start using it to gather information about your block devices. Running blkid without any options will display all the block devices and their respective details:

sudo blkid

This command outputs sections of information for each device, which typically include the PARTUUID, UUID, type of file system, and sometimes labels.

Command Options

• -o: Output format, where you might choose a list, or device name only.

• -s TAG: Show specific TAGs only, like UUID or TYPE.

• -t TAG=VALUE: Search for devices with a specific TAG value, like finding all devices with a specific type of filesystem.

Advanced Usage

For advanced scripts, you might want to parse the output of blkid. It provides a predictable and parse-able format that can be integrated into shell scripts. Take an example where you need only the UUID of a specific partition:

blkid -o value -s UUID /dev/sda1

This will return just the UUID of /dev/sda1 without additional formatting, perfect for scripting purposes!

Conclusion

Understanding how to use the blkid command is essential for managing and identifying block devices in Linux. With its installation being straightforward across different distributions thanks to apt, dnf, and zypper, you can easily integrate it into your system management toolkit. Whether it's for scripted automation or regular system checks, blkid offers the precise data handling and reporting capabilities needed for effective Linux system administration. Remember to always run such tools with the necessary permissions (usually root) to ensure they function as intended.