Update dotfiles script to automate xCode CLI tools

[iamnewton]

• Create a script to check if xCode is installed; if so inform the user,
  if not run automated install script of xCode CLI tools
• Create a recursive script to automate xCode CLI tools; checks version
  of kernel to ensure user is on 13 or up (Mavericks) as thats when
  xcode-select --install was introduced.

Issue: #33

[necolas]

Thanks! This looks great. I'm pretty swamped at the moment but will get to this when I next work on my dotfiles.

[iamnewton]

No problem, you probably don't need this anymore, if you're on OSX 10.9+ & you use the newest version of Homebrew install. They are doing an xCode command line tools install for you now. Although one thing to note about that; it will break your Homebrew installation of macvim as that requires the full xCode installation.

If you're interested I've forked your repo and "improved" (depends on your perspective) upon it with more features, such as...

• Using a Brewfile to install all homebrew packages
• Script to change login shells to new homebrew installed version
• Change out Pathogen for Vim (uses submodules) for Vundle (automates everything for you)
• Logs to the console.app as well as stdout and allows you to run in silent mode

[alrra]

If I remember correctly, type_exists 'gcc' will be true on OS X 10.9, even if XCode is not installed.

For OS X 10.9, I personally use:

if [ $(xcode-select -p &> /dev/null; printf $?) -ne 0 ]; then
     xcode-select --install 
     # ...
fi

[iamnewton]

Interesting, I get that xcode-select -p prints out the location of the xCode developer directory if available, (and the redirect to the null device), but what does the printf $? do? Isn't that supposed to print out the previous command?

[alrra]

what does the printf $? do?

@chrisopedia printf $? prints the exit code of the last executed command (in this case xcode-select -p &> /dev/null).

[iamnewton]

So the assumption here then is that xcode select -p will print out an exit code that is not equal to 0? What happens or is it possible that they could change their exit code? What about if there is no status number with their exit as in just plain exit? Does that still pass?

[alrra]

What happens or is it possible that they could change their exit code? What about if there is no status number with their exit as in just plain exit? Does that still pass?

@chrisopedia in any UNIX based system every command returns an exit code (from 0-255). 0 means true/successful completion, while != 0 means false/something went wrong.

For more in-depth information, please read: http://tldp.org/LDP/abs/html/exit-status.html.

xcode select -p will print out an exit code that is not equal to 0?

@chrisopedia xcode-select -p &> /dev/null; printf $? will print out the exit code for xcode-select -p no matter what value it is. Then, -ne 0 will check if that exit code is different then 0, and if it is, then XCode will need to be installed.

[iamnewton]

Cool @alrra I'll update my pull request with this new check.

[alrra]

@chrisopedia again, please note that this is only for OS X 10.9+. :)

[iamnewton]

K. Will do.