apache

apachectl commandhttpd [-d serverroot] [-f config] [-D parameter]

Apache HTTP Server (httpd) is one of the most widely used web server software packages. It serves static and dynamic content over HTTP/HTTPS, supporting virtual hosting, URL rewriting, authentication, and extensive module-based extensibility.The apachectl script provides a convenient interface for controlling the Apache daemon. It can operate as a simple front-end to the httpd command, or act as a SysV init script translating one-word arguments like start, restart, and stop into appropriate signals.Configuration is primarily done through httpd.conf and related files. The modular architecture allows enabling features like SSL/TLS (modssl), URL rewriting (modrewrite), proxying (modproxy), and dynamic content via CGI, PHP, or modwsgi.Apache supports multiple Multi-Processing Modules: prefork (process-based) for compatibility, worker (threaded), and event (threaded with improved keep-alive handling) for higher concurrency.

start

Start the Apache httpd daemon.

Stop the daemon immediately.

Restart the daemon (aborts current connections).

Gracefully restart (finish current requests, then restart).

Gracefully stop (finish current requests, then stop).

Check configuration file syntax.

Display full server status (requires mod_status and a text-based browser).

Show version number.

Show version and build parameters.

List compiled-in modules.

List all loaded modules (static and shared).

Test configuration syntax (same as configtest).

Show parsed virtual host settings.

Specify an alternate configuration file.

Define a parameter for use in configuration conditionals.

Configuration changes require a restart or reload. Syntax errors in configuration files prevent startup; always run configtest first. The graceful restart is preferred for production to avoid dropping active connections. Log files can grow large and require rotation. The apachectl script returns exit code 0 on success and >0 on error.

The Apache HTTP Server originated from the NCSA HTTPd server at the University of Illinois. In 1995, a group of developers began collaborating on patches, leading to the "patchy server" name that became Apache. The Apache Software Foundation was formed in 1999 to support its development. Apache dominated web server market share for over two decades, though nginx has gained significant ground since 2010.

nginx(8), httpd(8), htpasswd(1), ab(1)