Add a support for pip unknown commands

tests/rules/test_pip_unknown_command.py

@@ -0,0 +1,24 @@
+import pytest
+from thefuck.types import Command
+from thefuck.rules.pip_unknown_command import match, get_new_command
+
+
+@pytest.fixture
+def pip_unknown_cmd():
+    return '''ERROR: unknown command "instatl" - maybe you meant "install"'''
+
+
+@pytest.fixture
+def pip_unknown_cmd_without_recommend():
+    return '''ERROR: unknown command "i"'''
+
+
+def test_match(pip_unknown_cmd, pip_unknown_cmd_without_recommend):
+    assert match(Command('pip instatl', '', pip_unknown_cmd), None)
+    assert not match(Command('pip i', '', pip_unknown_cmd_without_recommend),
+                     None)
+
+
+def test_get_new_command(pip_unknown_cmd):
+    assert get_new_command(Command('pip instatl', '', pip_unknown_cmd), None)\
+        == 'pip install'

thefuck/rules/pip_unknown_command.py

@@ -0,0 +1,15 @@
+import re
+
+
+def match(command, settings):
+    return ('pip' in command.script and
+            'unknown command' in command.stderr and
+            'maybe you meant' in command.stderr)
+
+
+def get_new_command(command, settings):
+    broken_cmd = re.findall(r'ERROR: unknown command \"([a-z]+)\"',
+                            command.stderr)[0]
+    new_cmd = re.findall(r'maybe you meant \"([a-z]+)\"', command.stderr)[0]
+
+    return command.script.replace(broken_cmd, new_cmd, 1)