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After installing the GNU compilers, you may want to check out the HOWTO for installing Open MPI on Mac OS X.

Table of Contents
This HOWTO will guide you through the installation of the GNU C, C++ and Fortran compilers on Mac OS X.

One of the nice things about Mac OS X is that you have a polished user interface atop a Unix operating system. This means that using command line utilities such as compilers is straightforward, making coding on your Mac easy. If you have a multi-core Mac (most should by now) and would like to run codes that use MPI to distribute processing across multiple processor cores, you should also check out the HOWTO for installing Open MPI on Mac OS X. Note that you'll need to follow the instructions on this page prior to installing Open MPI if you don't already have some set of compilers installed.


To install the GNU compilers as described in this HOWTO, you'll need the following:

Video instructions for Mac OS 10.11 (El Capitan) with Xcode 7

Rough video transcript:

Hello, and welcome to this screencast on how to install the GNU C, C++ and Fortran compilers for Mac OS 10.11 (El Capitan). In this video, I will show you how to install the compilers as well as Apple’s Xcode software, which is required for the compiler installation. For this video, I am assuming you are using a Mac running Mac OS 10.11, also known as El Capitan, that you have an Apple App Store account and that you have internet access. I am also assuming you have administrator access on your Mac, allowing you to install software. If you’re running an older version of Mac OS X, the installation procedure will be similar, but you can check out the link at the end of this video for the installation procedure on older versions of Mac OS X back to 10.6.

Step 1: We’ll begin by installing the current version of Apple’s Xcode software, Xcode 7. To install Xcode, start by opening the App Store app by clicking on the Apple logo on the top left of the menu bar and then selecting App Store… Once the App Store app opens, enter "Xcode" into the search and press Enter. You can now click install to install Xcode. You may be prompted to enter your Apple ID and password if you’ve not previously installed applications via the App Store. Xcode is a pretty big download, so depending on the speed of your internet connection it may take some time to download and install. I’ll be back once the install is complete.

Step 2: Xcode has been downloaded and installed, and now we can move on to a critical second step for the Xcode install, installing the command line tools. To do this, we can use Spotlight to open the Terminal app. If you’re installing compilers, I am going to assume you’re at least somewhat familiar with using a terminal emulator. If not, you should still be able to do the install by following these instructions carefully. Once Terminal has opened, type in xcode-select --install. This will install the command line tools for Xcode, and you will be asked to perform the install using the typical application installation process. This may include asking you for your password.

Step 3: Now that Xcode is fully installed, we can move on to downloading the GNU compilers from the High-Performance Computing for Mac OS X website. The easiest way to get there is to open a web browser, Safari in this case. And type in "High-performance computing Mac OS X" in the Google search. It should be the top hit. On that page, we’ll grab the latest STABLE version of the GCC compiler package and click the link to download.

Step 4: After the compilers have downloaded, we can return to the Terminal and navigate to the Downloads directory. We’ll install the compilers now using the `sudo` command, and before we do so, I’m going to give you a little warning. Using the sudo command can do major damage to your computer if you aren’t careful, so please type the following exactly as shown to do the install: sudo tar -xvf gcc-5.3-bin.tar -C /. If your downloaded package ends in .tar.gz, you’ll need to add z to the list of flags after the tar command. This should take just a moment and will install the compilers in /usr/local.

Step 5: Now the compilers are installed, and if you’re running Mac OS 10.11, you should be able to test the installation by typing gcc -v. It should show version 5.3. You can try the same with the Fortran compiler by typing gfortran -v. If they return the compiler versions as expected, you’re all set. Enjoy.
- If your compilers are not installed, you may need to add the installation location to the PATH environment variable, which tells the computer where to look for command line programs.
- In that case, the easiest thing to do is go to the installation HOWTO at the link at the end of this video and check out the last section of the instructions for the installation for Mac OS 10.9 or 10.10. There are some additional instructions that may help resolve your issues. If you’re still having trouble, double check you’ve followed the instructions exactly as given in the video and feel free to add a comment if you still need some help.
- OK, so that’s it. Thank you for watching. If you have any comments, please leave them below. In case you’re interested, here’s another link to a video on how to install the Open MPI software for running multi-core applications on your Mac using MPI, the message-passing interface. Good luck!

Instructions for older versions of Mac OS X (10.6 - 10.10)

Instructions for installing the GNU compilers for older versions of Mac OS X (10.6 - 10.10) have been moved and are available on another page.

Tips & Warnings

I mention all but the last of these tips and warnings in the text above, but it doesn't hurt to list them a second time...

  • Beware that using sudo can do major damage to your computer if you aren't careful.
  • Note that after installing Xcode, you also need to perform a critical additional step.
    • Launch Xcode and install any available updates. Quit Xcode.
    • Launch (in /Applications/Utilities, hopefully you know that)
    • Install the Command Line Tools for OS X by typing

      xcode-select --install 

      This will open a dialog box to install the Command Line Tools for Xcode package. Install following the standard procedure.

  • If the correct version of gcc is not being found at the command line after installation, it is possible that you're using a terminal emulator that reads the .bashrc file rather than the .bash_profile file. To confirm, do the following:
    • Open a new terminal window using your terminal emulator of choice. This will reread the either the .bash_profile file or the .bashrc. If the new gcc version is not returned when typing

      gcc -v

      then your terminal emulator may be reading the .bashrc file.

    • You can fix this one of two ways
      • Create a symbolic link called .bashrc that points to .bash_profile by typing

        ln -s ~/.bash_profile ~/.bashrc
      • Modify the order of directories that are searched for commands by typing

        echo 'export PATH=/usr/local/bin:$PATH' >> ~/.bashrc


  1. Anonymous

    Thank you so much. Glad to see there is still support for snow leopard. (smile)

  2. Anonymous

    Indeed a much simpler solution to get gfortran, if one is not requiring the latest version, is using the distribution taken care by the R team (cran) :

    This is a simple "double clicakble" install solution, with its pros and cons.

    More generally, all version (for OS X 10.4, 10.5+) are available at

  3. Anonymous

    Really useful. Thank you 


  4. Anonymous

    Thanks a lot for the guide!

  5. Anonymous

    small type, missed ".gz" in sudo tar xvf gcc-4.9-bin.tar<.gz> -C /

    otherwise – many thanks for this

  6. Anonymous

    Hello Everybody.
    If I install the hpc-compiler on my mac(with mavericks), what does it happens to xcode 5?
    Does everything works on my osx?

  7. Anonymous

    Recently, I updated my OS X to 10.9 (Mavericks); unfortunately, gfortran stops working although I updated command line for Xcode 5.1.1 for  OS X Mavericks. I follow all the instruction you did mention above step by step, and installed gfortran successfully; however when I start running my fortran codes, I got the following errors ; e.g.

    $ gfortran function1.f90

    Undefined symbols for architecture x86_64:

      "_main", referenced from:

         implicit entry/start for main executable

    ld: symbol(s) not found for architecture x86_64

    collect2: error: ld returned 1 exit status

    I would be very gratify if you could kindly guide me how I could solve this problem. 



  8. Anonymous

    Thank you very much.

    I'm using xcode 3 with snow leopard. 

    when I type: echo 'export PATH=/usr/local/bin:$PATH' >> ~/.bash_profile

    The output is: Permission denied

     Can someone please help me? 

    Thank you


  9. Thanks for the feedback folks, glad this is useful. I just noticed that there are comments on this page when updating for Yosemite (I don't get notification of comments).

    Re: The double-clickable install of gfortran, this is good to know. The Mac HPC folks are prompt about making new releases available, so that's why I wanted to create this page.

    Re: The HPC compilers and Xcode, everything should be compatible if you install to /usr/local. Nothing will be overwritten by the HPC GNU compilers, and you can then select the compilers you'd like to use by editing your .bash_profile or .bashrc.

    @Michael: You're likely not to check this, but I'll reply anyway. I suspect you might be getting a mix of Xcode and new GNU compiler libraries in your environment. If you happen to see this, it would be helpful to know what the commands 'which gcc' and 'which gfortran' produce. It is possible things are not mixing nicely.

    @John: Strange. What does the command 'cat ~/.bash_profile' produce? What about 'ls -l ~/.bash_profile'?