Inital Import

README.md

@@ -1,2 +1,23 @@
 # xAODTutorials
 Some scripts to get started with basic things
+
+## Introduction
+
+Scripts in here are meant to be stand alone and do some very simple thing.
+
+## Setting up a standard RootCore directory
+
+In order to access a xAOD file you need a RootCore release. This script builds
+one from scratch. It is meant to be run from a machine similar to the tev
+machines.
+
+Usage:
+
+    source access_xAOD_from_command_line.sh ../RootCoreDir
+
+You should run from a new shell. It will leave your shell setup and ready.
+You can then type:
+
+     root -l $ROOTCOREDIR/scripts/load_packages.C DAOD_TRUTH0.testmeout.pool.root
+
+The load_packages.C configures ROOT for accessing the xAOD file. If that ran successfully you'll get no errors.

access_xAOD_from_command_line.sh

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+#
+# Run this file to generate a directory from which you can type
+#
+#   root '$ROOTCOREDIR/scripts/load_packages.C' <xaod-filename.root>
+#
+# The load_packages.C configures ROOT to read xAOD files
+#
+# Usage:
+#  source access_xAOD_from_command_line.sh <dir>
+#
+# Where <dir> is a fully qualified (and can be cd'd to).
+# Expect that this is a new shell
+#
+
+if [ "x$1" == "x" ]; then
+  echo Usage: source access_xAOD_from_command_line.sh dir-to-build-in
+fi
+
+mkdir -p $1
+cd $1
+
+setupATLAS
+# Sets up the AnalysisBase (general purpose) release
+# Version 2.3.53 is matched to the release that genrated the xAOD.
+#    In this case that was 20.1.8.3.
+rcSetup Base,2.3.53
+
+# Compile
+rc find_packages
+rc compile
+
+# Everything is now setup for
+# root '$ROOTCOREDIR/scripts/load_packages.C' <xaod-file.root>
+