Merge pull request #561 from rest-for-physics/cris_add_install_script

Add interactive installation script and README

Author: cmargalejo

scripts/installation/README.md

@@ -0,0 +1,94 @@
+# Installation Scripts
+
+Interactive installer for [REST-for-Physics](https://github.com/rest-for-physics/framework) and its dependencies.
+
+## Quick start
+
+```bash
+bash install_rest.sh
+```
+
+The script is interactive and will guide you through each step.
+
+## Install modes
+
+### Mode 1 -- Server install
+
+For machines where ROOT, Geant4 and Garfield++ are already available system-wide
+(e.g. the `titan` cluster at Zaragoza).
+
+You will be asked for the path to the system `thisREST.sh` that loads the
+pre-installed environment. The script then clones, configures and builds only
+REST itself.
+
+### Mode 2 -- Full install from source
+
+For a fresh Ubuntu (22.04/24.04) or WSL system with nothing pre-installed.
+Builds everything from source:
+
+| Package       | Version                          |
+|---------------|----------------------------------|
+| ROOT          | 6.26.10                          |
+| Geant4        | 11.0.3 (with GDML + data)       |
+| Garfield++    | pinned commit `a993c5eb`         |
+| REST          | latest from `master`             |
+
+System dependencies are installed via `apt` (requires `sudo`).
+If `sudo` is not available the script offers to skip this step, assuming
+packages are already present.
+
+### Mode 3 -- CVMFS install
+
+For HEP clusters where CERN's CVMFS is mounted (e.g. NAF-IAXO at DESY, RHEL 9).
+Instead of building the dependencies, the script loads a CERN **LCG view** from
+`/cvmfs` (providing ROOT, Geant4, GSL and Garfield) and builds only REST on top.
+This needs no `sudo` and survives OS upgrades far better than a hand-built stack.
+
+You will be asked for the LCG view `setup.sh` (default: a tested el9 view,
+`LCG_109/x86_64-el9-gcc13-opt`). The script then sets up a small Garfield
+compatibility shim, clones REST, and builds it -- including `restG4` if Geant4
+integration is enabled.
+
+On clusters where `$HOME` is on AFS (not writable in-session), the script sets
+`REST_HOME` to a writable location so REST's per-user `.rest` directory works.
+
+## What the script does
+
+1. Installs system packages (mode 2, optional)
+2. Downloads and builds ROOT, Geant4, Garfield++ (mode 2),
+   or loads a CERN LCG view from `/cvmfs` (mode 3)
+3. Asks you to choose which REST libraries to enable
+4. Clones the REST framework and pulls submodules
+   (also the `restG4` package when Geant4 integration is enabled)
+5. Configures and builds REST with CMake
+6. Tests the installation (`restRoot`)
+7. Optionally adds the environment setup to `~/.bashrc`
+   (and ensures login shells source it, e.g. for SSH)
+
+## Options asked during installation
+
+- **Install directory** -- where REST source and build will live (default: `~/rest`)
+- **Libraries** -- all, a common subset, or pick individually
+- **Garfield++ / Geant4 integration** -- enable or disable
+- **Submodule strategy** -- `--latest` commits (default) or the `--clean`
+  framework-recorded versions (pick `--clean` if a latest build fails to compile)
+- **Parallel jobs** -- capped at 16 for shared-server politeness
+
+## Individual scripts (legacy)
+
+The older per-package scripts are still available for reference:
+
+- `installROOT.sh` -- ROOT 6.28.02
+- `installGeant4.sh` -- Geant4 11.0.3
+- `installGarfield.sh` -- Garfield++
+- `installRequiredSoftware.sh` -- system packages via `apt-get`
+
+`install_rest.sh` supersedes all of them in a single guided workflow.
+
+## Requirements
+
+- **OS**: Ubuntu 22.04 / 24.04 (or WSL with either) for mode 2; any Linux with
+  CERN CVMFS mounted for mode 3 (e.g. RHEL 9 / NAF). Other distros may work but
+  the mode-2 `apt` package list would need adapting.
+- **Disk**: ~5 GB for a full build (ROOT + Geant4 + Garfield + REST)
+- **Tools**: `bash`, `git`, `python3`, `cmake`, `make`, `wget`