Hall A Analyzer

h1. Installing ROOT from a CERN binary distribution

Getting a ROOT binary distribution to work is actually very easy if your system matches the one the distribution was built for exactly. In particular, the compiler version should match as closely as possible. Here's how:

# Download the installation file (usually a @tar@ ball)

# Open a terminal

# Create a directory where you wish to install ROOT, for example @~/Apps@, and go there:

<pre>

APPS=~/Apps       # in tcsh: set APPS=~/Apps

mkdir -p $APPS

cd $APPS

</pre>

# Unpack the tar file into this directory. ROOT will be put in a subdirectory called @root@:

<pre>

tar xf <where-you-downloaded-root-tarfile>/root_v6.08.06.Linux-centos7-x86_64-gcc4.8.tar.gz   # change file name as appropriate

</pre>

# Finally, you need to run ROOT's setup script to configure your environment:

<pre>

source $APPS/root/bin/thisroot.sh

</pre>

See also [[ROOT Installation Guide#Testing your installation|Testing the installation]].

If no binary distribution available from CERN matches your platform exactly, things may still work. Suppose the ROOT distribution was built with a slightly older compiler than the one available on your system, for example, but everything else matches, it may be worth a try. For example, CERN's ROOT compiled for macOS 10.13 High Sierra labeled "clang90" appears to work with the latest Xcode, which provides "clang91". However, should you get strange error messages when running ROOT later, you know that you've probably been unsuccessful. At that point, it would be time to [[Building ROOT from source|build ROOT from source]].