What is L flag in htaccess rewrite rule

The [L] flag (or [last]) in Apache’s mod_rewrite tells the server to stop processing subsequent rewrite rules if the current rule matches. It acts as a “short-circuit,” preventing unnecessary processing of remaining rules in .htaccess or server configuration files. It is crucial for controlling redirection flow and preventing rule conflicts. Apache Software Foundation +2

Key Details About the [L] Flag:

• Stop Processing: If a RewriteRule matches and [L] is applied, the engine immediately terminates the current round of rule processing.
• Looping Behavior: While it stops the current pass, mod_rewrite may still restart the entire rule-checking process (loop) if a URL was modified, allowing for multiple refinements.
• Use Cases: Essential when you have finished redirecting a specific URL and do not want it to be altered by subsequent rules.
• Forced Application: The [L] flag is automatically assumed if a RewriteRule performs an external redirect. Stack Overflow +2

Example:

apache

RewriteRule ^page1\.html$ /page2.html [L]
RewriteRule ^page2\.html$ /final-page.html [R=301]

If a user requests page1.html, the [L] flag ensures it is rewritten to page2.html and stops. Without [L], the second rule might turn page2.html into final-page.html immediately.