Bug report:

[cabo]

(Remember to run brew update; brew cleanup; brew cask cleanup before reporting your issue. It usually fixes things!)

Description of issue

Installing macdown fails because /usr/local/bin is not writable

Output of brew cask <command> --verbose

$ brew cask install macdown --verbose
==> Downloading https://github.com/uranusjr/macdown/releases/download/v0.6/MacDown.app.zip
Already downloaded: /Library/Caches/Homebrew/macdown-0.6.zip
==> Verifying checksum for Cask macdown
==> It seems there is already an App at '/Applications/MacDown.app'; not moving.
==> Symlinking Binary 'macdown' to '/usr/local/bin/macdown'
==> ln: /usr/local/bin/macdown: Permission denied
Error: Command failed to execute!

==> Failed command:
["/bin/ln", "-hfs", "--", "#<Pathname:/Applications/MacDown.app/Contents/SharedSupport/bin/macdown>", "#<Pathname:/usr/local/bin/macdown>"]

==> Output of failed command:


==> Exit status of failed command:
#<Process::Status: pid 12807 exit 1>
Error: Kernel.exit

Output of brew doctor

...
Warning: Your Homebrew is not installed to /usr/local
...

Yes, that is true.

Output of brew cask doctor

==> Homebrew Version:
Homebrew 0.9.9 (git revision 0306209; last commit 2016-06-01)
Homebrew/homebrew-core (git revision 83bfb4; last commit 2016-06-01)

[cabo]

Oh, this seems to be a duplicate of #21372
It really violates the principle of least surprise...

[vitorgalvao]

You haven’t run brew update; brew cleanup; brew cask cleanup.