Server Side Includes (SSI) is a simple interpreted server-side scripting language used almost exclusively for the World Wide Web. It is most useful for including the contents of one or more files into a web page on a web server (see below), using its #include
directive. This could commonly be a common piece of code throughout a site, such as a page header, a page footer and a navigation menu. SSI also contains control directives for conditional features and directives for calling external programs. It is supported by Apache, LiteSpeed, nginx, IIS as well as W3C's Jigsaw.[1] It has its roots in NCSA HTTPd.[2]
In order for a web server to recognize an SSI-enabled HTML file and therefore carry out these instructions, either the filename should end with a special extension, by default .shtml
, .stm
, .shtm
, or, if the server is configured to allow this, set the execution bit of the file.[3]
ncsa-ssi
was invoked but never defined (see the help page).