diff --git a/setup/file_permissions.rst b/setup/file_permissions.rst
index 89fb4157f82..66ba709a132 100644
--- a/setup/file_permissions.rst
+++ b/setup/file_permissions.rst
@@ -1,86 +1,19 @@
 Setting up or Fixing File Permissions
 =====================================
 
-One important Symfony requirement is that the ``var`` directory must be
-writable both by the web server and the command line user.
+In Symfony 3.x, you needed to do some extra work to make sure that your cache directory
+was writable. But that is no longer true! In Symfony 4, everything works automatically:
 
-On Linux and macOS systems, if your web server user is different from your
-command line user, you need to configure permissions properly to avoid issues.
-There are several ways to achieve that:
+* In the ``dev`` environment, ``umask()`` is used in ``bin/console`` and ``web/index.php``
+  so that any created files are writable by everyone.
 
-1. Use the same User for the CLI and the Web Server
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Edit your web server configuration (commonly ``httpd.conf`` or ``apache2.conf``
-for Apache) and set its user to be the same as your CLI user (e.g. for Apache,
-update the ``User`` and ``Group`` directives).
-
-.. caution::
-
-    If this solution is used in a production server, be sure this user only has
-    limited privileges (no access to private data or servers, execution of
-    unsafe binaries, etc.) as a compromised server would give to the hacker
-    those privileges.
-
-2. Using ACL on a System that Supports ``chmod +a`` (macOS)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-On macOS systems, the ``chmod`` command supports the ``+a`` flag to define an
-ACL. Use the following script to determine your web server user and grant the
-needed permissions:
-
-.. code-block:: terminal
-
-    $ rm -rf var/cache/*
-    $ rm -rf var/log/*
-
-    $ HTTPDUSER=$(ps axo user,comm | grep -E '[a]pache|[h]ttpd|[_]www|[w]ww-data|[n]ginx' | grep -v root | head -1 | cut -d\  -f1)
-    $ sudo chmod +a "$HTTPDUSER allow delete,write,append,file_inherit,directory_inherit" var
-    $ sudo chmod +a "$(whoami) allow delete,write,append,file_inherit,directory_inherit" var
-
-3. Using ACL on a System that Supports ``setfacl`` (Linux/BSD)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Most Linux and BSD distributions don't support ``chmod +a``, but do support
-another utility called ``setfacl``. You may need to install ``setfacl`` and
-`enable ACL support`_ on your disk partition before using it. Then, use the
-following script to determine your web server user and grant the needed permissions:
-
-.. code-block:: terminal
-
-    $ HTTPDUSER=$(ps axo user,comm | grep -E '[a]pache|[h]ttpd|[_]www|[w]ww-data|[n]ginx' | grep -v root | head -1 | cut -d\  -f1)
-    # if this doesn't work, try adding `-n` option
-    $ sudo setfacl -dR -m u:"$HTTPDUSER":rwX -m u:$(whoami):rwX var
-    $ sudo setfacl -R -m u:"$HTTPDUSER":rwX -m u:$(whoami):rwX var
+* In the ``prod`` environment (i.e. when ``APP_ENV`` is ``prod`` and ``APP_DEBUG``
+  is ``0``), as long as you run ``php bin/console cache:warmup``, no cache files
+  will need to be written to disk at runtime.
 
 .. note::
 
-    The first ``setfacl`` command sets permissions for future files and folders,
-    while the second one sets permissions on the existing files and folders.
-    Both of these commands assign permissions for the system user and the Apache 
-    user.
-
-    ``setfacl`` isn't available on NFS mount points. However, storing cache and
-    logs over NFS is strongly discouraged for performance reasons.
-
-4. Without Using ACL
-~~~~~~~~~~~~~~~~~~~~
-
-If none of the previous methods work for you, change the umask so that the
-cache and log directories are group-writable or world-writable (depending
-if the web server user and the command line user are in the same group or not).
-To achieve this, put the following line at the beginning of the ``bin/console``,
-``public/index.php`` and ``public/index.php`` files::
-
-    umask(0002); // This will let the permissions be 0775
-
-    // or
-
-    umask(0000); // This will let the permissions be 0777
-
-.. note::
-
-    Changing the umask is not thread-safe, so the ACL methods are recommended
-    when they are available.
-
-.. _`enable ACL support`: https://help.ubuntu.com/community/FilePermissionsACLs
+    If you decide to store log files on disk, you *will* need to make sure your
+    logs directory (e.g. ``var/log/``) is writable by your web server user and
+    terminal user. One way this can be done is by using ``chmod 777 -R var/log/``.
+    Just be aware that your logs are readable by any user on your production system.