Homebrew: “Permission denied @ rb_file_s_symlink…”

In case you encounter this error below when doing brew update:

==> Homebrew has enabled anonymous aggregate formula and cask analytics.
Read the analytics documentation (and how to opt-out) here:
No analytics have been recorded yet (nor will be during this `brew` run).

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Updated 1 tap (homebrew/core).
No changes to formulae.
Error: Failed to link all completions, docs and manpages:
  Permission denied @ rb_file_s_symlink - (../../../Homebrew/completions/zsh/_brew, /usr/local/share/zsh/site-functions/_brew)
?  tfm git:(master) ? sudo chown -R $(whoami) $(brew --prefix)/*

Copy-and-paste the following in your terminal:

sudo chown -R $(whoami) $(brew --prefix)/*

How to install jshell via Homebrew

At the time of this writing, Java 9 is in beta. I installed because I wanted to check out jshell, Java’s new REPL (read-evaluate-print-loop). On top of the below, I brew-installed jenv (a must for managing different JDK versions).

$ brew install Caskroom/versions/java9-beta
$ jenv add /Library/Java/JavaVirtualMachines/jdk-9.jdk/Contents/Home
$ jenv shell oracle64-9-ea
$ java -version
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+102-2016-01-21-003129.javare.4316.nc)
Java HotSpot(TM) 64-Bit Server VM (build 9-ea+102-2016-01-21-003129.javare.4316.nc, mixed mode)
$ jshell
|  Welcome to JShell -- Version 9-ea
|  Type /help for help

-> "Hello JDK 9!"
|  Expression value is: "Hello JDK 9!"
|    assigned to temporary variable $1 of type String

I also did the following to get jshell to work:

1. Added to ~/.bash_profile

eval "$(jenv init -)"

2. Added my hostname in /etc/hosts


Cheers, and enjoy learning lambdas!