File vs Directory Permissions

File vs Directory Permissions How They Behave Differently

Files and directories follow the same permission bit system, but the effect of r, w, x is **completely different between them. Misunderstanding this is one of the top causes of WordPress upload, plugin install, CLI, and SSH access issues. This module ensures you never break file access on your VPS.

What You Will Learn

• Difference between file and directory permission behavior.
• How r, w, x apply differently on files vs folders.
• Why directories require x to enter.
• WordPress-specific consequences (uploads, plugins, wp-cli).
• Real secure production permission examples.
• Debugging matrix + command lab + checks.

5W + 1H Framework

Question	Answer
What	distinction between file and directory permissions
Why	reading, editing, uploading, executing WP tasks
Where	/var/www/, wp-content/, logs, scripts
When	deployments, fixing upload issues, security hardening
Who	owner / group / www-data / dev users
How	using chmod + understanding bit semantics

Core Principle

Files = content access

Directories = container access (enter, list, modify)

Even if a file is readable, you cant access it if directory permissions block you.

Permission Semantics Table

For Files

Bit	Meaning
r	can read file contents
w	can modify file contents
x	can execute file (scripts, binaries)

For Directories

Bit	Meaning
r	list files (ls)
w	create/delete/rename files in it
x	enter directory (cd, access files)

Directory Execute (x) = Access Permit / Door Key

Without x, directory is visible but inaccessible.

Practical Real-World Comparison

Action	File Needs	Directory Needs
Read file content	r	x
Edit file	w	x
Run script	x	x
List directory	—	r + x
Enter directory	—	x
Create/delete file	—	w + x

WordPress-Specific Rules

Function	Required Permission
View site content	files need 644
Upload images	wp-content/uploads needs 755
Install plugins/themes	directories need x
Run wp-cli	files 644, dirs 755
Secure wp-config	600

WP Standard Permissions (Numeric)

Type	Recommended
Files	644
Directories	755
wp-config.php	600

WP Standard Permissions (Symbolic)

Type	Recommended
Files	chmod u=rw,go=r
Directories	chmod u=rwx,go=rx
wp-config.php	chmod u=rw,go=

Command + Expected Output

Set correct WP perms

find . -type d -exec chmod 755 {} ;
find . -type f -exec chmod 644 {} ;
chmod 600 wp-config.php

Check:

ls -l

Expected snippet:

-rw-r--r--  wp-settings.php
drwxr-xr-x  wp-content
-rw-------  wp-config.php

Common Misconfig Mistakes

Mistake	Result
Directory 644	Cannot enter folder, WP breaks
Files 755	Public executes, security risk
uploads 644	Cannot upload images
wp-config 777	Critical security hole

Static vs Dynamic Approach

Mode	When
Static (644/755)	production default
Dynamic permission patch	troubleshooting uploads/plugins
Harden config (600)	after setup

Go-Live Checklist

Check	Command
File perms	find . -type f -perm 777
Dir perms	find . -type d -perm 777
Config perms	stat wp-config.php
Directory traversal	ls -ld wp-content/

Goal:

files readable, directories traversable, config locked.

Troubleshooting Matrix

Symptom	Root Cause	Fix
Uploads fail	missing x on directories	chmod -R 755 wp-content/uploads
Plugins fail	wrong folder perms	find . -type d -exec chmod 755 {} ;
403 forbidden browsing dirs	+x missing	chmod a+X wp-content
WP CLI fails creating files	no write on dir	chmod g+w wp-content/uploads

Quick Lab

Fix core WP perms & test directory traversal

cd /var/www/your-site/public_html

find . -type d -exec chmod 755 {} ;
find . -type f -exec chmod 644 {} ;
chmod 600 wp-config.php

ls -ld wp-content/
ls -l wp-config.php

Verify success:

• /wp-content/ is drwxr-xr-x
• wp-config.php is rw-------

Cheat Sheet

Files → need r to read, w to edit, x to execute
Directories → need x to enter, r to list, w to create/delete

Essential:

Files: 644
Directories: 755
wp-config: 600

Mental rule:

x on files = execute script

x on directories = enter the folder

Mini-Quiz

1. Directory without x?

• Can't enter

1. File without r?

• Can't read

1. Directory listing requires?

• r + x

1. WP folders default?

• 755

1. wp-config secure mode?

• 600