Table of Contents

The find command recursively searches directories and evaluates each file path against an expression you define. It is one of the most important Linux tools for file discovery, cleanup tasks, and automation pipelines.

Overview

Use find when you need to:

  • Locate files by name, type, size, age, owner, or permissions
  • Execute actions on matched files (for example, delete, move, or run another command)
  • Build reliable automation with null-safe output for paths that contain spaces
  • Combine search criteria using logical operators for precise matching

Syntax

find [path...] [expression]

The command has two major parts:

  1. path...: One or more starting directories (for example, ., /var/log, /home/user).
  2. expression: Tests, actions, options, and operators evaluated left to right.

If you omit the path, find defaults to the current directory (.).

Core Concepts

Common Tests

Test Purpose Example
-name Case-sensitive filename match (glob pattern) -name "*.log"
-iname Case-insensitive filename match -iname "readme.md"
-type Match file type (f, d, l, etc.) -type f
-size Match by size (k, M, G) -size +100M
-mtime Modified time in days -mtime -7
-mmin Modified time in minutes -mmin -30
-user Match file owner -user root
-group Match group owner -group developers
-perm Match permissions -perm 644

Common Actions

Action Purpose Example
-print Print matching path (default in many cases) -print
-print0 Print null-delimited paths (safe for scripting) -print0
-delete Delete matches -type f -name "*.tmp" -delete
-exec Run command per match -exec rm -f {} \;
-exec ... + Run command in batches -exec rm -f {} +
-ls Print long listing style output -ls

Logical Operators

Operator Meaning Notes
-a Logical AND Default between adjacent terms
-o Logical OR Use parentheses to control precedence
! Logical NOT Negates the next test/expression
( ... ) Group expression Escape in shell: \( and \)

Common Options

Option Purpose Example
-maxdepth N Limit recursion depth -maxdepth 2
-mindepth N Skip top levels before matching -mindepth 1
-xdev Stay on one filesystem -xdev
-L Follow symbolic links -L
-P Do not follow symbolic links (default) -P
-H Follow symlinks listed on command line -H

Examples

find . -type f -name "*.md"

# Find directories named .git and prune them from traversal
find . -type d -name ".git" -prune -o -type f -name "*.md" -print

# Find files modified in the last 24 hours
find /var/log -type f -mtime -1

# Find files larger than 500 MB
find /data -type f -size +500M

# Find empty files and directories
find . -empty

# Safe pipeline: null-delimited output to xargs
find . -type f -name "*.log" -print0 | xargs -0 grep -n "ERROR"

# Batch-delete temporary files safely
find . -type f -name "*.tmp" -exec rm -f {} +

# Delete empty directories (review first without -delete)
find . -type d -empty
find . -type d -empty -delete

Safe Usage Guidelines

  1. Start with a non-destructive preview command before using -delete.
  2. Prefer -print0 with xargs -0 for whitespace-safe scripting.
  3. Use -maxdepth and -mindepth to prevent accidental broad scans.
  4. Use -xdev when scanning system paths to avoid crossing mounted filesystems.
  5. Quote glob patterns ("*.log") so the shell does not expand them before find runs.

Performance Tips

  1. Restrict the search path to the smallest practical subtree.
  2. Put cheap and highly selective tests early in expressions.
  3. Use pruning (-prune) to skip large directories such as dependency caches.
  4. Prefer -exec ... + to reduce process creation overhead versus one command per file.

Troubleshooting

"paths must precede expression"

Cause: The shell expanded a wildcard before find parsed the expression.

Fix: Quote patterns, for example -name "*.txt".

Permission denied errors

Cause: The current user cannot read parts of the tree.

Fix: Run with elevated permissions if appropriate (sudo) or suppress noise:

find / -type f -name "*.conf" 2>/dev/null

Expression logic returns unexpected matches

Cause: -o precedence and implicit -a can be confusing.

Fix: Group logic explicitly:

find . \( -name "*.md" -o -name "*.txt" \) -type f

Notes

find behavior is provided by GNU findutils on most Linux distributions. Run man find for full platform-specific details.

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