drupal/core/INSTALL.txt

CONTENTS OF THIS FILE
---------------------

 * Requirements and notes
 * Optional server requirements
 * Installation
 * Reinstall
 * Building and customizing your site
 * Multisite configuration
 * Multilingual configuration

REQUIREMENTS AND NOTES
----------------------

Drupal requires:

- A web server with PHP support, for example:
  - Apache 2.0 (or greater) (http://httpd.apache.org/).
  - Nginx 1.1 (or greater) (http://nginx.com/).
- PHP 5.4.5 (or greater) (http://php.net/). For better security support it is
  recommended to update to at least 5.5.21 or 5.6.5.
- One of the following databases:
  - MySQL 5.5.3 (or greater) (http://www.mysql.com/).
  - MariaDB 5.5.20 (or greater) (https://mariadb.org/). MariaDB is a fully
    compatible drop-in replacement for MySQL.
  - Percona Server 5.5.8 (or greater) (http://www.percona.com/). Percona
    Server is a backwards-compatible replacement for MySQL.
  - PostgreSQL 8.3 (or greater) (http://www.postgresql.org/).
  - SQLite 3.4.2 (or greater) (http://www.sqlite.org/).

For more detailed information about Drupal requirements, including a list of
PHP extensions and configurations that are required, see "System requirements"
(https://www.drupal.org/requirements) in the Drupal.org online documentation.

For detailed information on how to configure a test server environment using a
variety of operating systems and web servers, see "Local server setup"
(https://www.drupal.org/node/157602) in the Drupal.org online documentation.

Note that all directories mentioned in this document are always relative to the
directory of your Drupal installation, and commands are meant to be run from
this directory (except for the initial commands that create that directory).

OPTIONAL SERVER REQUIREMENTS
----------------------------

- If you want to use Drupal's "Clean URLs" feature on an Apache web server, you
  will need the mod_rewrite module and the ability to use local .htaccess
  files. For Clean URLs support on IIS, see "Clean URLs with IIS"
  (https://www.drupal.org/node/3854) in the Drupal.org online documentation.

- If you plan to use XML-based services such as RSS aggregation, you will need
  PHP's XML extension. This extension is enabled by default on most PHP
  installations.

- To serve gzip compressed CSS and JS files on an Apache web server, you will
  need the mod_headers module and the ability to use local .htaccess files.

- Some Drupal functionality (e.g., checking whether Drupal and contributed
  modules need updates, RSS aggregation, etc.) require that the web server be
  able to go out to the web and download information. If you want to use this
  functionality, you need to verify that your hosting provider or server
  configuration allows the web server to initiate outbound connections. Most web
  hosting setups allow this.

- PHP 5.5.21 provides features for improved security when used with MySQL. While
  this is not required, it is highly encouraged to use PHP 5.5.21 or 5.6.5 and
  above.

INSTALLATION
------------

1. Download and extract Drupal.

   You can obtain the latest Drupal release from https://www.drupal.org -- the
   files are available in .tar.gz and .zip formats and can be extracted using
   most compression tools.

   To download and extract the files, on a typical Unix/Linux command line, use
   the following commands (assuming you want version x.y.z of Drupal in .tar.gz
   format):

     wget https://www.drupal.org/files/projects/drupal-x.y.z.tar.gz
     tar -zxvf drupal-x.y.z.tar.gz

   This will create a new directory drupal-x.y.z/ containing all Drupal files
   and directories. Then, to move the contents of that directory into a
   directory within your web server's document root or your public HTML
   directory, continue with this command:

     mv drupal-x.y.z/* drupal-x.y.z/.htaccess drupal-x.y.z/.csslintrc drupal-x.y.z/.editorconfig drupal-x.y.z/.eslintignore drupal-x.y.z/.eslintrc /path/to/your/installation

2. Create the Drupal database.

   Because Drupal stores all site information in a database, the Drupal
   installer will attempt to create this database for you. If you create the
   database manually, you must grant Drupal certain database privileges (such as
   the ability to create tables).  For details, consult INSTALL.mysql.txt,
   INSTALL.pgsql.txt, or INSTALL.sqlite.txt. You may also need to consult your
   web hosting provider for instructions specific to your web host.

   Take note of the username, password, database name, and hostname as you
   create the database. You will enter this information during the install.

3. Run the install script.

   To run the install script, point your browser to the base URL of your
   website (e.g., http://www.example.com).

   You will be guided through several screens to set up the database, add the
   site maintenance account (the first user, also known as user/1), and provide
   basic web site settings.

   During installation, several files and directories need to be created, which
   the install script will try to do automatically. However, on some hosting
   environments, manual steps are required, and the install script will tell
   you that it cannot proceed until you fix certain issues. This is normal and
   does not indicate a problem with your server.

   The most common steps you may need to perform are:

   a. Missing files directory.

      The install script will attempt to create a file storage directory in
      the default location at sites/default/files (the location of the files
      directory may be changed after Drupal is installed).

      If auto-creation fails, you can make it work by changing permissions on
      the sites/default directory so that the web server can create the files
      directory within it for you. (If you are creating a multisite
      installation, substitute the correct sites directory for sites/default;
      see the Multisite Configuration section of this file, below.)

      For example, on a Unix/Linux command line, you can grant everyone
      (including the web server) permission to write to the sites/default
      directory with this command:

        chmod a+w sites/default

      Be sure to set the permissions back after the installation is finished!
      Sample command:

        chmod go-w sites/default

      Alternatively, instead of allowing the web server to create the files
      directory for you as described above, you can create it yourself. Sample
      commands from a Unix/Linux command line:

        mkdir sites/default/files
        chmod a+w sites/default/files

   b. Missing settings file.

      Drupal will try to automatically create settings.php and services.yml
      files, which are normally in the directory sites/default (to avoid
      problems when upgrading, Drupal is not packaged with this file). If
      auto-creation of either file fails, you will need to create the file
      yourself. Use the template sites/default/default.settings.php or
      sites/default/default.services.yml respectively.

      For example, on a Unix/Linux command line, you can make a copy of the
      default.settings.php and default.services.yml files with the commands:

        cp sites/default/default.settings.php sites/default/settings.php
        cp sites/default/default.services.yml sites/default/services.yml

      Next, grant write privileges to the file to everyone (including the web
      server) with the command:

        chmod a+w sites/default/settings.php
        chmod a+w sites/default/services.yml

      Be sure to set the permissions back after the installation is finished!
      Sample command:

        chmod go-w sites/default/settings.php
        chmod go-w sites/default/services.yml

   c. Write permissions after install.

      The install script will attempt to write-protect the settings.php file and
      the sites/default directory after saving your configuration. If this
      fails, you will be notified, and you can do it manually. Sample commands
      from a Unix/Linux command line:

        chmod go-w sites/default/settings.php
        chmod go-w sites/default/services.yml
        chmod go-w sites/default

4. Verify that the site is working.

   When the install script finishes, you will be logged in with the site
   maintenance account on a "Welcome" page. If the default Drupal theme is not
   displaying properly and links on the page result in "Page Not Found" errors,
   you may be experiencing problems with clean URLs. Visit
   https://www.drupal.org/getting-started/clean-urls to troubleshoot.

5. Change file system storage settings (optional).

   The files directory created in step 4 is the default file system path used to
   store all uploaded files, as well as some temporary files created by
   Drupal. After installation, you can modify the file system path to store
   uploaded files in a different location.

   It is not necessary to modify this path, but you may wish to change it if:

   - Your site runs multiple Drupal installations from a single codebase (modify
     the file system path of each installation to a different directory so that
     uploads do not overlap between installations).

   - Your site runs on a number of web servers behind a load balancer or reverse
     proxy (modify the file system path on each server to point to a shared file
     repository).

   - You want to restrict access to uploaded files.

   To modify the file system path:

   a. Ensure that the new location for the path exists and is writable by the
      web server. For example, to create a new directory named uploads and grant
      write permissions, use the following commands on a Unix/Linux command
      line:

        mkdir uploads
        chmod a+w uploads

   b. Navigate to Administration > Configuration > Media > File system, and
      enter the desired path. Note that if you want to use private file storage,
      you need to first enter the path for private files and save the
      configuration, and then change the "Default download method" setting and
      save again.

   Changing the file system path after files have been uploaded may cause
   unexpected problems on an existing site. If you modify the file system path
   on an existing site, remember to copy all files from the original location
   to the new location.

6. Revoke documentation file permissions (optional).

   Some administrators suggest making the documentation files, especially
   CHANGELOG.txt, non-readable so that the exact version of Drupal you are
   running is slightly more difficult to determine. If you wish to implement
   this optional security measure, from a Unix/Linux command line you can use
   the following command:

     chmod a-r CHANGELOG.txt

   Note that the example only affects CHANGELOG.txt. To completely hide all
   documentation files from public view, repeat this command for each of the
   Drupal documentation files in the installation directory, substituting the
   name of each file for CHANGELOG.txt in the example.

   For more information on setting file permissions, see "Modifying Linux,
   Unix, and Mac file permissions" (https://www.drupal.org/node/202483) or
   "Modifying Windows file permissions" (https://www.drupal.org/node/202491) in
   the Drupal.org online documentation.

7. Set up independent "cron" maintenance jobs.

   Many Drupal modules have tasks that must be run periodically, including the
   Search module (building and updating the index used for keyword searching),
   the Aggregator module (retrieving feeds from other sites), and the System
   module (performing routine maintenance and pruning of database tables). These
   tasks are known as "cron maintenance tasks", named after the Unix/Linux
   "cron" utility.

   When you install Drupal, its built-in cron feature is enabled, which
   automatically runs the cron tasks periodically, triggered by people visiting
   pages of your site. You can configure the built-in cron feature by navigating
   to Administration > Configuration > System > Cron.

   It is also possible to run the cron tasks independent of site visits; this is
   recommended for most sites. To do this, you will need to set up an automated
   process to visit the page /cron on your site, which executes the cron
   tasks.

   The URL of the cron page requires a "cron key" to protect against
   unauthorized access. Your site's cron key is automatically generated during
   installation and is specific to your site. The full URL of the page, with the
   cron key, is available in the "Cron maintenance tasks" section of the Status
   report page at Administration > Reports > Status report.

   As an example for how to set up this automated process, you can use the
   crontab utility on Unix/Linux systems. The following crontab line uses the
   wget command to visit the cron page, and runs each hour, on the hour:

   0 * * * * wget -O - -q -t 1 http://example.com/cron/YOURKEY

   Replace the text "http://example.com/cron/YOURKEY" in the example with the
   full URL displayed under "Cron maintenance tasks" on the "Status report"
   page.

   More information about cron maintenance tasks is available at
   https://www.drupal.org/cron, and sample cron shell scripts can be found in
   the core/scripts/ directory. (Note that these scripts must be customized like
   the above example, to add your site-specific cron key and domain name.)

REINSTALL
------------

Drupal can be reinstalled without downloading and extracting the Drupal release.

1. Drop all the tables in your database.

2. Remove everything in sites/default/files.

3. Remove sites/default/settings.php.

4. Follow the Installation Instructions above starting from Step 3 (Run the
   install script).

BUILDING AND CUSTOMIZING YOUR SITE
----------------------------------

A new installation of Drupal defaults to a very basic configuration. To extend
your site, you use "modules" and "themes". A module is a plugin that adds
functionality to Drupal, while a theme changes the look of your site. The core
of Drupal provides several optional modules and themes, and you can download
more at https://www.drupal.org/project/project_module and
https://www.drupal.org/project/project_theme

Do not mix downloaded or custom modules and themes with Drupal's core modules
and themes. Drupal's modules and themes are located in the /core/modules and
/core/themes directories, while the modules and themes you add to Drupal are
normally placed in the /modules and /themes directories. If you run a multisite
installation, you can also place modules and themes in the site-specific
directories -- see the Multisite Configuration section, below.

Never edit Drupal's core modules and themes; instead, use the hooks available in
the Drupal API. To modify the behavior of Drupal, develop a module as described
at https://www.drupal.org/developing/modules. To modify the look of Drupal,
create a subtheme as described at https://www.drupal.org/node/2165673, or a
completely new theme as described at https://www.drupal.org/documentation/theme

MULTISITE CONFIGURATION
-----------------------

A single Drupal installation can host several Drupal-powered sites, each with
its own individual configuration.

For this to work you need the file sites/sites.php to exist. Make a copy of
the example.sites.php file:

  $ cp sites/example.sites.php sites/sites.php

Additional site configurations are created in subdirectories within the 'sites'
directory. Each subdirectory must have a 'settings.php' file, which specifies
the configuration settings. The easiest way to create additional sites is to
copy file 'default.settings.php' from the 'sites/default' directory into the
new site directory with file name 'settings.php' and modify as appropriate.
The new directory name is constructed from the site's URL. The configuration
for www.example.com could be in 'sites/example.com/settings.php' (note that
'www.' should be omitted if users can access your site at http://example.com/).

  $ cp sites/default/defaults.settings.php sites/example.com/settings.php

Sites do not have to have a different domain. You can also use subdomains and
subdirectories for Drupal sites. For example, example.com, sub.example.com, and
sub.example.com/site3 can all be defined as independent Drupal sites. The setup
for a configuration such as this would look like the following:

  sites/default/settings.php
  sites/example.com/settings.php
  sites/sub.example.com/settings.php
  sites/sub.example.com.site3/settings.php

When searching for a site configuration (for example www.sub.example.com/site3),
Drupal will search for configuration files in the following order, using the
first configuration it finds:

  sites/www.sub.example.com.site3/settings.php
  sites/sub.example.com.site3/settings.php
  sites/example.com.site3/settings.php
  sites/www.sub.example.com/settings.php
  sites/sub.example.com/settings.php
  sites/example.com/settings.php
  sites/default/settings.php

If you are installing on a non-standard port, the port number is treated as the
deepest subdomain. For example: http://www.example.com:8080/ could be loaded
from sites/8080.www.example.com/. The port number will be removed according to
the pattern above if no port-specific configuration is found, just like a real
subdomain.

Each site configuration can have its own site-specific modules and themes in
addition to those installed in the standard 'modules' and 'themes' directories.
To use site-specific modules or themes, simply create a 'modules' or 'themes'
directory within the site configuration directory. For example, if
sub.example.com has a custom theme and a custom module that should not be
accessible to other sites, the setup would look like this:

  sites/sub.example.com/
    settings.php
    themes/custom_theme
    modules/custom_module

For more information about multiple virtual hosts or the configuration
settings, consult https://www.drupal.org/documentation/install/multi-site

For more information on configuring Drupal's file system path in a multisite
configuration, see step 6 above.

MULTILINGUAL CONFIGURATION
--------------------------

By default, Drupal is installed in one language, and further languages may be
installed later.

For detailed instructions, visit
https://www.drupal.org/documentation/multilingual