locate and updatedb Commands in Linux: Fast File Search

Quick take: locate filename searches a prebuilt database and returns results nearly instantly. Run sudo updatedb to refresh the database when files have been added or removed since the last daily update.

What Is the locate Command in Linux?

The locate command finds files by searching a prebuilt index of the filesystem rather than scanning directories in real time. This makes it dramatically faster than find for full-filesystem searches — a search that would take find minutes returns with locate in under a second.

The trade-off is currency: the database is rebuilt by updatedb, which runs automatically daily on most systems. Files created or deleted since the last update will be missing or still listed.

Install locate

# Ubuntu / Debian (classic)
sudo apt install mlocate

# Ubuntu 22.04+ (faster plocate, recommended)
sudo apt install plocate

# RHEL / CentOS / Rocky
sudo dnf install mlocate

# Build the initial database after install
sudo updatedb

Syntax

locate [OPTIONS] PATTERN

The pattern is matched as a substring anywhere in the full file path. locate nginx matches /etc/nginx/nginx.conf, /usr/sbin/nginx, and /var/log/nginx/.

Common Options

Practical Examples

# Find all files containing 'nginx' in their path
locate nginx

# Case-insensitive search
locate -i SSH_CONFIG

# Find only files named exactly 'nginx.conf' (basename match)
locate -b '\nginx.conf'

# Count how many files match
locate -c '*.conf'

# Limit to first 10 results
locate -l 10 python

# Only show results that still exist on disk (removes stale entries)
locate -e '*.log'

# Use regex pattern
locate -r '\.py$'

# Find PHP files under /var/www
locate /var/www | grep '\.php$'

The backslash in '\nginx.conf' is a plocate/mlocate extension that disables substring matching on the basename — it matches only the exact basename nginx.conf.

updatedb — Refresh the Database

updatedb rebuilds the file path database that locate reads. It scans the filesystem and writes a compressed index.

# Rebuild the database (requires root)
sudo updatedb

# Check when the database was last updated
stat /var/lib/mlocate/mlocate.db

# Exclude certain paths from indexing (edit the config)
# /etc/updatedb.conf — PRUNEPATHS and PRUNEFS control exclusions
cat /etc/updatedb.conf

Common directories excluded by default: /proc, /sys, /tmp, network mounts. Edit /etc/updatedb.conf to add more exclusions if your server has large scratch directories you never need to search.

locate vs find

Use locate when: you need fast results, you are searching the whole system for a file you know exists, and freshness is not critical.

Use find when: you need current results (files created minutes ago), you need to filter by size, permissions, or modification time, or you need to execute actions on the matched files.

A practical pattern: use locate for discovery (find the path), then use find for precision (filter to the exact file).

plocate vs mlocate — Which Should You Use?

Ubuntu 22.04+ ships plocate as the default, replacing the older mlocate. plocate uses a compressed trigram index that is 10–20x faster than mlocate's linear scan for substring searches, and the database is significantly smaller.

Both use the same command syntax and the same updatedb configuration at /etc/updatedb.conf. If you have an existing script using locate, it works without changes after switching to plocate.

Configuring updatedb.conf — Excluding Directories

The /etc/updatedb.conf file controls what updatedb indexes. Large directories full of generated files (build artifacts, container layers, node_modules) should be excluded to keep the database small and updatedb fast.

cat /etc/updatedb.conf

PRUNE_BIND_MOUNTS="yes"
PRUNEPATHS="/tmp /var/spool /media /var/lib/os-prober /var/lib/ceph"
PRUNEFS="NFS nfs nfs4 rpc_pipefs afs binfmt_misc proc smbfs autofs iso9660 ncpfs coda devpts ftpfs devfs mfs shfs sysfs cifs lustre tmpfs usbfs udf fuse.glusterfs fuse.sshfs curlftpfs ecryptfs fusesmb devtmpfs"

# Add custom exclusions (edit the file)
sudo nano /etc/updatedb.conf
# Add to PRUNEPATHS (space-separated):
# PRUNEPATHS="/tmp /var/spool ... /var/lib/docker /home/user/node_modules"

# Rebuild after changing config
sudo updatedb

Using locate in Shell Scripts

#!/bin/bash
# Find all .conf files for a service and check if they exist on disk
SERVICE="nginx"
echo "Config files for $SERVICE:"
locate -e "$SERVICE" | grep "\.conf$" | while read -r file; do
    if [ -r "$file" ]; then
        echo "  [readable] $file"
    else
        echo "  [no read] $file"
    fi
done

# Count total indexed paths
TOTAL=$(locate -c "")
echo "Total indexed paths: $TOTAL"

Common Errors and Fixes

Reference: locate man page — man7.org. Tested on Ubuntu 22.04 LTS with plocate 1.1.15.

Final Thoughts

locate is the fastest way to find a file when you know part of its name and do not need real-time accuracy. Add sudo updatedb to your workflow after major file operations so searches remain useful. For time-sensitive or attribute-based searches, find is the right tool.