link: add --force and --dry-run options

`brew link` can now be made to delete any conflicting files using
the --force argument. It also has a --dry-run option, similar to
git clean -n, which will list any files which would be deleted
without touching the filesystem.

Closes Homebrew/homebrew#11811.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/Library/Homebrew/cmd/link.rb b/Library/Homebrew/cmd/link.rb
index 8ac280c0d..c5e34fe2c 100644
--- a/Library/Homebrew/cmd/link.rb
+++ b/Library/Homebrew/cmd/link.rb
@@ -9,14 +9,30 @@ module Homebrew extend self
       abort "Cowardly refusing to `sudo brew link'"
     end
 
+    if ARGV.force?
+      mode = :force
+    elsif ARGV.include?("--dry-run") || ARGV.include?("-n")
+      mode = :dryrun
+    else
+      mode = nil
+    end
+
     ARGV.kegs.each do |keg|
       if keg.linked_keg_record.directory? and keg.linked_keg_record.realpath == keg
         opoo "Already linked: #{keg}"
         next
       end
 
+      if mode == :dryrun
+        print "Would remove:\n" do
+          keg.link(mode)
+        end
+
+        next
+      end
+
       print "Linking #{keg}... " do
-        puts "#{keg.link} symlinks created"
+        puts "#{keg.link(mode)} symlinks created"
       end
     end
   end