locate Command - Fast File Search

What Is the locate Command?

The locate command helps you find files and directories quickly by searching a pre-built database of filesystem paths.

Unlike find, which searches through directories on the filesystem, locate looks up matching paths in an existing database. This makes it especially useful when you need to locate a file quickly on a system containing many files.

The main trade-off is that search results depend on how recently the database was updated.

Installation

On Ubuntu systems, locate may not be installed by default. One commonly used implementation is plocate.

Install it with:

sudo apt update
sudo apt install plocate

Verify the installation:

locate --version

Basic Syntax

locate [options] pattern

• options : Optional flags that control the search.
• pattern : The filename or text pattern to look for in stored paths.

Common locate Commands

1. Search for a File

locate error.txt

Displays database entries whose paths match error.txt.

For example:

/home/ubuntu/error.txt
/var/log/error.txt

The results show stored paths that match the search pattern. They do not guarantee that every listed file still exists on the filesystem.

Note: locate error.txt can match paths containing that text, not only files whose exact name is error.txt.

To match a filename more precisely, use:

locate -b '\error.txt'

The -b option matches the basename, and the escaped pattern treats the filename literally.

2. Count Matching Paths (-c)

Use -c to count matching database entries instead of printing each path.

locate -c telusko.txt

The output might be:

3

This means three matching entries were found in the database. It does not necessarily mean that three matching files currently exist.

3. Search Without Considering Case (-i)

Use -i to ignore differences between uppercase and lowercase letters.

locate -i exception.txt

This can match paths containing names such as exception.txt, Exception.txt, or EXCEPTION.TXT.

How Does the locate Database Work?

The locate utility uses an index of filesystem paths stored in a database, commonly maintained by a tool such as updatedb.

The process works as follows:

1. Database creation or update: The system scans eligible filesystem locations and records paths in the database.
2. Search: When you run locate, it searches the stored index.
3. Results: Matching paths are displayed without requiring a new directory-by-directory scan for every search.

This approach makes locate fast, but its results can become outdated when files are created, renamed, or deleted.

Database updates may be scheduled automatically, depending on the Linux distribution and system configuration.

Updating the Database

Suppose you create a new file:

touch exception.txt

You then search for it:

locate exception.txt

If the database has not been updated since the file was created, the file may not appear in the results.

To refresh the database, run:

sudo updatedb

Then search again:

locate exception.txt

The updated database should now include the file, provided its directory is covered by the database configuration and accessible to the indexing process.

You do not need to run updatedb after every file creation. Use it when you need to refresh the index and the expected result is missing.

Summary

• locate is a fast way to search for files and directories by path.
• It searches an index rather than scanning the filesystem from scratch.
• Use -c to count matching paths and -i for case-insensitive searches.
• Run sudo updatedb when you need to refresh the database, subject to your system's configuration and permissions.
• Choose locate for speed and find when you need current filesystem results or more detailed search conditions.

Remember: locate prioritizes speed by searching an index, while find searches the filesystem directly.

Written By: Muskan Garg