How to Use the Command 'findfs' (with examples)

The findfs command is a powerful utility in the Linux operating system that aids in locating filesystems based on specific identifiers such as labels or UUIDs (Universally Unique Identifiers). This command is particularly useful in scenarios where you need to identify filesystem details without browsing through mount points or physically checking the device description. It greatly simplifies the process of retrieving filesystem information, especially in environments with numerous storage devices.

Use Case 1: Search Block Devices by Filesystem Label

Code:

findfs LABEL=label

Motivation:

Suppose you have a set of external drives connected to your system, each with a designated label for easy identification such as “backup2023”, “photos”, or “music”. Over time, the physical naming of these drives might become inconsistent or forgotten. Using the findfs command with the label option allows you to quickly and easily locate the specific filesystem associated with a particular label, ensuring you access the correct storage unit.

Explanation:

• findfs: This is the base command invoked to find the filesystem.
• LABEL=label: This argument specifies the label of the filesystem you are searching for. The “label” here should be replaced with the actual label assigned to your filesystem.

Example Output:

/dev/sdb1

In this example, the output indicates that the filesystem labeled as ’label’ is located on the device /dev/sdb1.

Use Case 2: Search by Filesystem UUID

Code:

findfs UUID=uuid

Motivation:

Identifying filesystems by UUID is a reliable method since UUIDs are unique to each filesystem and remain constant across system reboots and mount/umount operations. If you’re configuring fstab entries or need to ensure that system scripts always target the same filesystem regardless of device name changes, using findfs with a UUID becomes essential.

Explanation:

• findfs: The command used to find the filesystem.
• UUID=uuid: The UUID is a universally unique identifier assigned to a filesystem. Replace “uuid” with the actual UUID of your filesystem. This method eliminates any ambiguity that might arise from using device names which can change between reboots.

Example Output:

/dev/sda2

Here, the command has located the filesystem with the specified UUID on the device /dev/sda2.

Use Case 3: Search by Partition Label (GPT or MAC Partition Table)

Code:

findfs PARTLABEL=partition_label

Motivation:

Modern partitioning schemes, such as GPT, allow partitions themselves to be labeled separately from the filesystems residing on them. If you’ve labeled your partitions for organizational purposes, you can use this feature to quickly pinpoint the device node corresponding to a particular partition, which can be especially useful in systems with multiple partitions per drive.

Explanation:

• findfs: The command you use to find the filesystem.
• PARTLABEL=partition_label: This specifies the partition label you have assigned. You should replace “partition_label” with the actual label of your partition.

Example Output:

/dev/nvme0n1p3

This output suggests that the partition with the given label is located on the device /dev/nvme0n1p3.

Use Case 4: Search by Partition UUID (GPT Partition Table Only)

Code:

findfs PARTUUID=partition_uuid

Motivation:

Similar to filesystem UUIDs, partition UUIDs provide a unique identifier for each partition in a GPT setup. This is particularly useful in scripts and automated tasks where consistent and reliable identification of partitions is necessary. Finding a partition using its UUID ensures precise operation, unaffected by changes in hardware or device enumeration order.

Explanation:

• findfs: The command employed to find the filesystem belonging to the specified partition.
• PARTUUID=partition_uuid: This argument specifies the UUID of the partition you’re interested in. Here, “partition_uuid” is replaced by the actual partition UUID.

Example Output:

/dev/sdc4

In this example, the command successfully identifies /dev/sdc4 as the partition with the specified UUID.

Conclusion:

The findfs command is an indispensable tool for Linux users who need to manage multiple filesystems and partitions efficiently. With its ability to locate filesystems and partitions via labels and UUIDs, it simplifies many administrative tasks, making it easier to maintain system integrity and manage storage resources effectively. By using the examples above, users can harness the full potential of findfs to navigate their system’s storage landscape with ease.