docs: code example reformatting

Add labeled fences to most code blocks, monospace terms where
appropriate, omit "$" when referring to variables

1 files changed, 7 insertions, 5 deletions

diff --git a/docs/External-Commands.md b/docs/External-Commands.md
index d3a590f16..7cc7380a0 100644
--- a/docs/External-Commands.md
+++ b/docs/External-Commands.md
@@ -2,8 +2,8 @@
 
 Homebrew, like Git, supports *external commands*. This lets you create new commands that can be run like:
 
-```shell
-$ brew mycommand --option1 --option3 formula
+```sh
+brew mycommand --option1 --option3 formula
 ```
 
 without modifying Homebrew's internals.
@@ -11,7 +11,7 @@ without modifying Homebrew's internals.
 ## Command types
 External commands come in two flavors: Ruby commands and shell scripts.
 
-In both cases, the command file should be executable (`chmod +x`) and live somewhere in `$PATH`.
+In both cases, the command file should be executable (`chmod +x`) and live somewhere in `PATH`.
 
 ### Ruby commands
 An external command `extcmd` implemented as a Ruby command should be named `brew-extcmd.rb`. The command is executed by doing a `require` on the full pathname. As the command is `require`d, it has full access to the Homebrew "environment", i.e. all global variables and modules that any internal command has access to.
@@ -24,7 +24,7 @@ A shell script for a command named `extcmd` should be named `brew-extcmd`. This
 | Variable               | Description                                                                                                                                                                 |
 |------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | `HOMEBREW_CACHE`       | Where Homebrew caches downloaded tarballs to, by default `~/Library/Caches/Homebrew`.                                                                                       |
-| `HOMEBREW_CELLAR`      | The location of the Homebrew Cellar, where software is staged. This will be `$HOMEBREW_PREFIX/Cellar` if that directory exists, or `$HOMEBREW_REPOSITORY/Cellar` otherwise. |
+| `HOMEBREW_CELLAR`      | The location of the Homebrew Cellar, where software is staged. This will be `HOMEBREW_PREFIX/Cellar` if that directory exists, or `HOMEBREW_REPOSITORY/Cellar` otherwise.   |
 | `HOMEBREW_LIBRARY_PATH`| The directory containing Homebrew’s own application code.                                                                                                                   |
 | `HOMEBREW_PREFIX`      | Where Homebrew installs software. This is always the grandparent directory of the `brew` executable, `/usr/local` by default.                                               |
 | `HOMEBREW_REPOSITORY`  | If installed from a Git clone, the repository directory (i.e. where Homebrew’s .git directory lives).                                                                       |
@@ -41,12 +41,13 @@ Check if there is a new upstream version of a formula.
 See the [`README`](https://github.com/youtux/homebrew-livecheck/blob/master/README.md) for more info and usage.
 
 Install using:
+
 ```sh
 brew tap youtux/livecheck
 ```
 
 ### brew-gem
-Install any gem package into a self-contained Homebrew cellar location: <https://github.com/sportngin/brew-gem>
+Install any `gem` package into a self-contained Homebrew Cellar location: <https://github.com/sportngin/brew-gem>
 
 Note this can also be installed with `brew install brew-gem`.
 
@@ -57,6 +58,7 @@ Get Growl notifications for Homebrew: <https://github.com/secondplanet/homebrew-
 Simple support for starting formulae using launchctl, has out of the box support for any formula which defines `startup_plist` (e.g. mysql, postgres, redis u.v.m.): <https://github.com/Homebrew/homebrew-services>
 
 Install using:
+
 ```sh
 brew tap homebrew/services
 ```