However, an “absolutely complete” list is technically impossible to print here in full—because the .htaccess file can use nearly any Apache directive that is allowed by the AllowOverride setting and enabled modules.

• The available directives change depending on your Apache version and enabled modules.
• New modules can add their own directives.
• Some directives are not allowed in .htaccess context (such as Listen, <VirtualHost>, etc).

BUT:
I can give you a very comprehensive list of all directives, rules, and commands that are commonly supported/used in .htaccess, including less common and advanced ones.
If you want the true, absolute list for your server, run:

httpd -L

on your own machine.

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📃 Comprehensive List of .htaccess Directives, Rules, and Commands

1. Rewrite & Redirect

• RewriteEngine
• RewriteBase
• RewriteCond
• RewriteRule
• RewriteMap (rarely used in .htaccess)
• Redirect
• RedirectMatch
• RedirectPermanent
• RedirectTemp
• RedirectGone

2. Authentication & Authorization

• AuthType
• AuthName
• AuthUserFile
• AuthGroupFile
• Require
• Satisfy
• Order (legacy, deprecated)
• Allow (legacy, deprecated)
• Deny (legacy, deprecated)

3. Directory Index & Error Documents

• DirectoryIndex
• ErrorDocument

4. MIME, Handlers, and Filters

• AddType
• AddEncoding
• AddCharset
• AddHandler
• RemoveHandler
• AddOutputFilter
• AddInputFilter
• RemoveOutputFilter
• RemoveInputFilter
• DefaultType
• TypesConfig

5. Access & Override Controls

• Options
• AllowOverride
• AccessFileName

6. Environment Variables & Headers

• SetEnv
• UnsetEnv
• PassEnv
• SetEnvIf
• SetEnvIfNoCase
• Header
• RequestHeader

7. Compression

• AddOutputFilterByType
• DeflateCompressionLevel
• DeflateBufferSize
• DeflateMemLevel
• DeflateWindowSize

8. Caching

• ExpiresActive
• ExpiresDefault
• ExpiresByType
• Cache-Control (via Header)
• CacheFile
• FileETag

9. Security / SSL

• SSLRequire
• SSLRequireSSL
• SSLOptions
• SSLVerifyClient
• SSLVerifyDepth

10. Custom Logging (via modules)

• CustomLog (rarely allowed)
• LogLevel
• LogFormat

11. Proxy / Remote

• ProxyPass
• ProxyPassReverse
• ProxyAddHeaders

12. Other Useful Directives

• AddLanguage
• AddDefaultCharset
• BrowserMatch
• BrowserMatchNoCase
• LanguagePriority
• ForceType
• IndexIgnore
• IndexOptions
• AddIcon
• AddDescription
• DefaultIcon
• FallbackResource
• Options +FollowSymLinks / -Indexes, etc.

13. File & Directory Specific

• <Files>
• <FilesMatch>
• <IfModule>
• <If>
• <IfDefine>
• <Limit>
• <LimitExcept>
• <Directory> (only in configs, not .htaccess)
• <Location> (not allowed in .htaccess)

14. CGI & Script

• ScriptAlias (rarely in .htaccess)
• ScriptInterpreterSource
• AddHandler cgi-script
• Options +ExecCGI

15. Miscellaneous

• TimeOut (rare, typically not allowed)
• Header set X-Frame-Options ...
• Header always ...
• SetHandler
• UnsetHandler
• Redirect 301 /old-url /new-url
• RewriteOptions
• RewriteLock

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⚡️ Advanced / Module-Specific Directives

Some directives are only available if certain modules are enabled.

• mod_security: SecRuleEngine, SecRule, etc.
• mod_evasive: DOSHashTableSize, etc.
• mod_qos: QS_SrvMaxConnPerIP, etc.
• mod_speling: CheckSpelling
• mod_deflate: SetOutputFilter, etc.

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Important Notes

• Not all directives are allowed in .htaccess context. It depends on how AllowOverride is set in your httpd.conf or vhost configuration.
• Some directives only work in server config, not in .htaccess.
• Modules like mod_rewrite, mod_headers, mod_expires, mod_deflate, etc., must be enabled in Apache for those directives to work.

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Authoritative, Up-to-date List

• The official list of all directives:
  https://httpd.apache.org/docs/current/mod/directives.html
• See which are valid in .htaccess (context column = “directory” or “.htaccess”)
  Apache Directive Contexts

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Summary Table of Most Used .htaccess Directives

Directive/Rule	Purpose/Use
RewriteEngine/Rule/Cond	URL rewriting and redirects
Redirect/RedirectMatch	Simple redirects
AuthType/AuthUserFile	Authentication
Require/Order/Allow/Deny	Access control
DirectoryIndex	Default index file
ErrorDocument	Custom error pages
AddType/AddHandler	MIME types and handlers
Options	Enable/disable features (Indexes, SymLinks)
ExpiresActive/ByType	Caching headers
Header	Set or modify HTTP headers
SetEnv/SetEnvIf	Environment variables
,	Target config to certain files

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