From b521ba0c7a6a9eddeb0b2f7b57fdd3163eb80bfd Mon Sep 17 00:00:00 2001
From: Mike McQuaid <mike@mikemcquaid.com>
Date: Wed, 30 Jan 2019 21:29:43 +0000
Subject: [PATCH] --prefix: use CLI::Parser.

---
 Library/Homebrew/cmd/--prefix.rb | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/Library/Homebrew/cmd/--prefix.rb b/Library/Homebrew/cmd/--prefix.rb
index 4a5e0ba77c..fb98235dcf 100644
--- a/Library/Homebrew/cmd/--prefix.rb
+++ b/Library/Homebrew/cmd/--prefix.rb
@@ -1,13 +1,25 @@
-#:  * `--prefix`:
-#:    Display Homebrew's install path. *Default:* `/usr/local` on macOS and `/home/linuxbrew/.linuxbrew` on Linux
-#:
-#:  * `--prefix` <formula>:
-#:    Display the location in the cellar where <formula> is or would be installed.
+require "cli_parser"
 
 module Homebrew
   module_function
 
+  def __prefix_args
+    Homebrew::CLI::Parser.new do
+      usage_banner <<~EOS
+        `--prefix` [<formula>]
+
+        Display Homebrew's install path. *Default:* `/usr/local` on macOS and
+        `/home/linuxbrew/.linuxbrew` on Linux.
+
+        If <formula> is provided, display the location in the cellar where <formula>
+        is or would be installed.
+      EOS
+    end
+  end
+
   def __prefix
+    __prefix_args.parse
+
     if ARGV.named.empty?
       puts HOMEBREW_PREFIX
     else