diff --git a/docs b/docs
index bc9d81b1..2cd0dce6 160000
--- a/docs
+++ b/docs
@@ -1 +1 @@
-Subproject commit bc9d81b1d34ecc70b60c83d4062c03e0b30e95db
+Subproject commit 2cd0dce683f40f5606bf7476d47e7bb052cfebba
diff --git a/platformio/commands/misc/__init__.py b/platformio/commands/system/__init__.py
similarity index 100%
rename from platformio/commands/misc/__init__.py
rename to platformio/commands/system/__init__.py
diff --git a/platformio/commands/misc/command.py b/platformio/commands/system/command.py
similarity index 96%
rename from platformio/commands/misc/command.py
rename to platformio/commands/system/command.py
index 757206b3..48336bfd 100644
--- a/platformio/commands/misc/command.py
+++ b/platformio/commands/system/command.py
@@ -18,14 +18,14 @@ import subprocess
 import click
 
 from platformio import proc
-from platformio.commands.misc.completion import (
+from platformio.commands.system.completion import (
     get_completion_install_path,
     install_completion_code,
     uninstall_completion_code,
 )
 
 
-@click.group("misc", short_help="Miscellaneous commands")
+@click.group("system", short_help="Miscellaneous system commands")
 def cli():
     pass
 
diff --git a/platformio/commands/misc/completion.py b/platformio/commands/system/completion.py
similarity index 96%
rename from platformio/commands/misc/completion.py
rename to platformio/commands/system/completion.py
index 032225c4..1a969203 100644
--- a/platformio/commands/misc/completion.py
+++ b/platformio/commands/system/completion.py
@@ -52,7 +52,7 @@ def install_completion_code(shell, path):
     if is_completion_code_installed(shell, path):
         return None
 
-    return click_completion.install(shell=shell, path=path)
+    return click_completion.install(shell=shell, path=path, append=shell != "fish")
 
 
 def uninstall_completion_code(shell, path):
diff --git a/tox.ini b/tox.ini
index e8e8bdb2..3db3a8ef 100644
--- a/tox.ini
+++ b/tox.ini
@@ -19,7 +19,7 @@ envlist = py27,py37,py38
 passenv = *
 usedevelop = True
 deps =
-    py36,py3,py38: black
+    py36,py37,py38: black
     isort
     pylint
     pytest