cli: Add the -d option to provide inline conf

README.rst

@@ -57,6 +57,9 @@ Usage
 
 .. code:: bash
 
+ # Use a pre-defined lint configuration
+ yamllint -d relaxed file.yml
+
  # Use a custom lint configuration
  yamllint -c ~/myconfig file.yml
 

docs/configuration.rst

@@ -8,7 +8,7 @@ settings can be gathered in a configuration file.
 To use a custom configuration file, either name it ``.yamllint`` in your working
 directory, or use the ``-c`` option:
 
-::
+.. code:: bash
 
  yamllint -c ~/myconfig file.yml
 
@@ -22,6 +22,15 @@ Unless told otherwise, yamllint uses its ``default`` configuration:
 
 Details on rules can be found on :doc:`the rules page <rules>`.
 
+There is another pre-defined configuration named ``relaxed``. As its name
+suggests, it is more tolerant.
+
+It can be chosen using:
+
+.. code:: bash
+
+ yamllint -d relaxed file.yml
+
 Extending the default configuration
 -----------------------------------
 
@@ -63,6 +72,21 @@ strict on block sequences indentation:
    indentation:
      indent-sequences: whatever
 
+Custom configuration without a config file
+------------------------------------------
+
+It is possible -- although not recommended -- to pass custom configuration
+options to yamllint with the ``-d`` (short for ``--config-data``) option.
+
+Its content can either be the name of a pre-defined conf (example: ``default``
+or ``relaxed``) or a serialized YAML object describing the configuration.
+
+For instance:
+
+.. code:: bash
+
+ yamllint -d "{extends: relaxed, rules: {line-length: {max: 120}}}" file.yml
+
 Errors and warnings
 -------------------
 

yamllint/cli.py

@@ -66,8 +66,11 @@ def run(argv=None):
                                      description=APP_DESCRIPTION)
     parser.add_argument('files', metavar='FILE_OR_DIR', nargs='+',
                         help='files to check')
-    parser.add_argument('-c', '--config', dest='config_file', action='store',
+    parser.add_argument('-c', '--config-file', dest='config_file',
-                        help='path to a custom configuration')
+                        action='store', help='path to a custom configuration')
+    parser.add_argument('-d', '--config-data', dest='config_data',
+                        action='store',
+                        help='custom configuration (as YAML source)')
     parser.add_argument('-f', '--format',
                         choices=('parsable', 'standard'), default='standard',
                         help='format for parsing output')
@@ -78,8 +81,17 @@ def run(argv=None):
 
     args = parser.parse_args(argv)
 
+    if args.config_file is not None and args.config_data is not None:
+        print('Options --config-file and --config-data cannot be used '
+              'simultaneously.', file=sys.stderr)
+        sys.exit(-1)
+
     try:
-        if args.config_file is not None:
+        if args.config_data is not None:
+            if ':' not in args.config_data:
+                args.config_data = 'extends: ' + args.config_data
+            conf = YamlLintConfig(content=args.config_data)
+        elif args.config_file is not None:
             conf = YamlLintConfig(file=args.config_file)
         elif os.path.isfile('.yamllint'):
             conf = YamlLintConfig(file='.yamllint')