Wiki software
PmWiki is a wiki-based content management system designed for a collaborative creation and maintenance of websites.
It is free software written in PHP, licensed under the terms of the GNU General Public License.
Design focus.
The PmWiki philosophy prioritizes writers over readers, aiming to facilitate easy document authoring despite limitations in document types. It supports collaborative website maintenance with built-in tools for access control, delegation, monitoring, review, and edit reversion. Ease of maintenance is a key design goal, and PmWiki is configurable and extensible, allowing independent updates to the core while maintaining compatibility with local customizations.
In addition to standard collaborative features like content management and knowledge bases, PmWiki is utilized by companies and groups as an internal communication platform offering tools for task management and meeting archives. It is also employed by university and research teams.
The PmWiki wiki markup includes unique features not found in other wiki engines. The PmWiki markup engine is customizable, and markup rules can be added, replaced or removed, and it can support other markup languages. As an example, the Creole specifications can be enabled. The edit form, since version 2.3.0, can have syntax highlighting enabled for its own wiki markup dialect.
Features.
Content storage.
PmWiki uses regular text files to store content. Each page of the wiki is stored in its own file on the web server. By default pages are stored in 8-bit or UTF-8 encoding, with page text, metadata, and revision history in the same file. According to the author, "For the standard operations (view, edit, page revisions), holding the information in flat files is clearly faster than accessing them in a database..."
The storage class is extensible, allowing add-ons to enable other storage systems and formats. For example, with add-ons, a website can use SQLite or MySQL databases, or XML files for storage.
PmWiki supports "attachments" (uploads: images or other files) to its wiki pages. The attachments can be versioned. There are PmWiki add-ons allowing easier management of the uploaded files, e.g. deletion or thumbnail/gallery creation.
Wiki structure.
Wiki pages are contained within namespaces, called "wiki groups". Multiple namespaces can be used, and each namespace can have its own configuration options, add-ons, access control, skin, styles, sidebar (menu), the language of the content, and interface.
Hierarchically, every page is contained in a namespace. It is possible to display and navigate through pages in a tree-like structure with a "wiki trail". Through recipes, it is possible to have a flat structure (no wiki groups), multiple nested groups, or sub-pages.
Special namespaces are "PmWiki", Site, SiteAdmin, and Category which contain the documentation and some configuration templates.
Markup.
The PmWiki markup shares similarities with MediaWiki. Here is a sample of commonly used markup rules.
Links are usually wrapped in double brackets, optionally with link text:
It is possible to enable internal links for CamelCase words without brackets, and add-ons can enable other link markups like codice_1.
Headings are preceded with exclamation marks:
It is possible to enable an automated table of contents coming with the PmWiki core, or install one among several Table of contents add-ons.
Lists are prefixed by "*" (bulleted) and "#" (numbered) and can be nested:
Directives for listing pages and attachments, and including pages and templates:
Other page directives allow setting the page title, description, and keywords, disabling layout sections like sidebars or footers, creating tables, or defining page text variables. Add-ons allow for extra functionality.
Inline markup:
Other markup rules can be enabled through recipes (add-ons).
HTML is not available for the edit form out of the box, but it is possible to enable selected tags through add-ons.
Skin templates.
PmWiki offers a skin template scheme that makes it possible to change the look and feel of the wiki or website with a high degree of flexibility in both functionality and appearance.
Since version 2.3.30, the core responsive skin can have a dark theme enabled. The dark mode functions are available for reuse by custom skins.
Access control.
PmWiki permits users and administrators to establish password protection for individual pages, groups of pages, or the entire site. For example, defined zones may be established to enable collaborative work by certain groups, such as in a company intranet.
Password protection can be applied to reading, editing, uploading to, and changing passwords for the restricted zone. The out-of-the-box installation uses "shared passwords" rather than login names, but a built-in option can enable a sophisticated user/group-based access control system on pages, groups of pages or the whole wiki.
PmWiki can use passwords from config files, special wiki pages, and .htpasswd/.htgroup files. There are also user-based authorization possibilities and authentication via various external sources (e.g. LDAP, forum databases, etc.).
Customization.
PmWiki follows a design philosophy with the main objectives of ease of installation, maintainability, and keeping non-required features out of the core distribution of the software. This design encourages customization with a wide selection of custom extensions, known as "recipes" available from the PmWiki Cookbook. Creating and maintaining extensions and custom installations is easy thanks to a number of well documented hooks in the wiki engine.
System requirements.
Recent PmWiki releases require a web server that can run PHP version 5.4 or more recent. PmWiki can be deployed to standard hosting providers, or locally. There is a "recipe" to allow running PmWiki "Standalone", with the PHP built-in webserver, for example from a USB flash drive.
Books and articles about PmWiki.
The following books analyse PmWiki, have dedicated chapters or sections, compare it with other wiki and CMS software:
PmWiki has been featured in a number of printed and online magazines including 
"Inc Magazine", Linux Gazette, "PCMag",
"LXer", "Framasoft, "Linuxfr".
The page PmWiki References lists publications about PmWiki in various languages.
References.
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