Advise the use of absolute paths, fixes #4259

doc/01-basic-usage.md

@@ -3,7 +3,7 @@
 ## Introduction
 
 For our basic usage introduction, we will be installing `monolog/monolog`,
-a logging library. If you have not yet installed Composer, refer to the 
+a logging library. If you have not yet installed Composer, refer to the
 [Intro](00-intro.md) chapter.
 
 > **Note:** for the sake of simplicity, this introduction will assume you
@@ -18,7 +18,7 @@ other metadata as well.
 ### The `require` Key
 
 The first (and often only) thing you specify in `composer.json` is the
-[`require`](04-schema.md#require) key. You're simply telling Composer which 
+[`require`](04-schema.md#require) key. You're simply telling Composer which
 packages your project depends on.
 
 ```json
@@ -29,8 +29,8 @@ packages your project depends on.
 }
 ```
 
-As you can see, [`require`](04-schema.md#require) takes an object that maps 
-**package names** (e.g. `monolog/monolog`) to **version constraints** (e.g. 
+As you can see, [`require`](04-schema.md#require) takes an object that maps
+**package names** (e.g. `monolog/monolog`) to **version constraints** (e.g.
 `1.0.*`).
 
 ### Package Names
@@ -53,7 +53,7 @@ In the previous example we were requiring version
 Monolog. This means any version in the `1.0` development branch. It is the
 equivalent of saying versions that match `>=1.0 <1.1`.
 
-Version constraints can be specified in several ways, read 
+Version constraints can be specified in several ways, read
 [versions](articles/versions.md) for more in-depth information on this topic.
 
 ### Stability
@@ -82,7 +82,7 @@ In case of Monolog it will put it into `vendor/monolog/monolog`.
 > `vendor` in your `.gitignore`. You really don't want to add all of that
 > code to your repository.
 
-You will notice the [`install`](03-cli.md#install) command also created a 
+You will notice the [`install`](03-cli.md#install) command also created a
 `composer.lock` file.
 
 ## `composer.lock` - The Lock File
@@ -94,8 +94,8 @@ to those specific versions.
 **Commit your application's `composer.lock` (along with `composer.json`)
 into version control.**
 
-This is important because the [`install`](03-cli.md#install) command checks 
-if a lock file is present, and if it is, it downloads the versions specified 
+This is important because the [`install`](03-cli.md#install) command checks
+if a lock file is present, and if it is, it downloads the versions specified
 there (regardless of what `composer.json` says).
 
 This means that anyone who sets up the project will download the exact same
@@ -111,9 +111,9 @@ versions from `composer.json` and  create the lock file after executing the
 [`update`](03-cli.md#update) or the [`install`](03-cli.md#install) command.
 
 This means that if any of the dependencies get a new version, you won't get the
-updates automatically. To update to the new version, use the 
-[`update`](03-cli.md#update) command. This will fetch the latest matching 
-versions (according to your `composer.json` file) and also update the lock file 
+updates automatically. To update to the new version, use the
+[`update`](03-cli.md#update) command. This will fetch the latest matching
+versions (according to your `composer.json` file) and also update the lock file
 with the new version.
 
 ```sh
@@ -141,8 +141,8 @@ means that you can automatically `require` any package that is available there.
 If you go to the [Packagist website](https://packagist.org/) (packagist.org),
 you can browse and search for packages.
 
-Any open source project using Composer is recommended to publish their packages 
-on Packagist. A library doesn't need to be on Packagist to be used by Composer, 
+Any open source project using Composer is recommended to publish their packages
+on Packagist. A library doesn't need to be on Packagist to be used by Composer,
 but it enables discovery and adoption by other developers more quickly.
 
 ## Autoloading
@@ -152,7 +152,7 @@ For libraries that specify autoload information, Composer generates a
 autoloading for free.
 
 ```php
-require 'vendor/autoload.php';
+require __DIR__ . '/vendor/autoload.php';
 ```
 
 This makes it really easy to use third party code. For example: If your project
@@ -165,7 +165,7 @@ $log->pushHandler(new Monolog\Handler\StreamHandler('app.log', Monolog\Logger::W
 $log->addWarning('Foo');
 ```
 
-You can even add your own code to the autoloader by adding an 
+You can even add your own code to the autoloader by adding an
 [`autoload`](04-schema.md#autoload) field to `composer.json`.
 
 ```json
@@ -183,8 +183,8 @@ You define a mapping from namespaces to directories. The `src` directory would
 be in your project root, on the same level as `vendor` directory is. An example
 filename would be `src/Foo.php` containing an `Acme\Foo` class.
 
-After adding the [`autoload`](04-schema.md#autoload) field, you have to re-run 
-[`dump-autoload`](03-cli.md#dump-autoload) to re-generate the 
+After adding the [`autoload`](04-schema.md#autoload) field, you have to re-run
+[`dump-autoload`](03-cli.md#dump-autoload) to re-generate the
 `vendor/autoload.php` file.
 
 Including that file will also return the autoloader instance, so you can store
@@ -192,12 +192,12 @@ the return value of the include call in a variable and add more namespaces.
 This can be useful for autoloading classes in a test suite, for example.
 
 ```php
-$loader = require 'vendor/autoload.php';
+$loader = require __DIR__ . '/vendor/autoload.php';
 $loader->add('Acme\\Test\\', __DIR__);
 ```
 
-In addition to PSR-4 autoloading, Composer also supports PSR-0, classmap and 
-files autoloading. See the [`autoload`](04-schema.md#autoload) reference for 
+In addition to PSR-4 autoloading, Composer also supports PSR-0, classmap and
+files autoloading. See the [`autoload`](04-schema.md#autoload) reference for
 more information.
 
 > **Note:** Composer provides its own autoloader. If you don't want to use that