What is locate?

The locate command is a fast file search tool that uses a pre-built database of file names and paths to quickly find matches, unlike find which searches the file system live.

Install locate (Red Hat / RHEL)

sudo dnf install mlocate

Then update the file database:

sudo updatedb

How locate Works

• It searches a database (usually /var/lib/mlocate/mlocate.db) that contains absolute paths of all files and directories.
• This database is not updated in real-time—you must run updatedb manually or via cron for fresh entries.

Basic Usage

Find a File by Name

locate filename.txt

Output:

/home/user/docs/filename.txt
/var/tmp/cache/filename.txt

Find All Instances of a Command

locate ls

Shows all paths with “ls” in their names.

Filtering with grep or --regex

Using grep to Filter

locate log | grep apache

Shows paths with both “log” and “apache”.

Using --regex for Regular Expression Matching

locate --regex '^/etc/.*\.conf$'

Explanation:

• ^/etc/: starts with /etc/
• .*: any characters
• \.conf$: ends with .conf

Output:

/etc/httpd/httpd.conf
/etc/ssh/sshd_config

Match a Specific File Extension

locate --regex '\.log$'

Finds all files ending with .log.

Match File Names Containing Digits

locate --regex '/[a-zA-Z0-9_-]*[0-9]+.*\.txt$'

Finds .txt files with digits in the name.

Match Hidden Files in Home Directory

locate --regex '^/home/[^/]+/\..*'

Explanation:

• ^/home/: must start in /home/
• [^/]+: matches username folder
• /\.: matches dotfiles
• .*: any characters

Refreshing the Database

Use updatedb when new files are added:

sudo updatedb

This updates /var/lib/mlocate/mlocate.db.

Permissions Note

locate may show results you don’t have permission to access. For privacy, RHEL may configure mlocate to only show files accessible by the current user.

Advantages vs find

Examples Summary