Add option to install script to install latest code (#664)

* Move optional steps for testing VMs out of README.md file
This may help avoid new users being confused that they must follow
those instructions.

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>

* Add option to new install.sh script to install latest version of source code

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>

---------

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>

Author: jafingerhut

README.md

@@ -108,16 +108,13 @@ for a list of virtual machine images that you can download, then use
 VirtualBox's File->Import Appliance menu item to add the virtual
 machine to those on your system.
 
+There is one user account:
++ Username: p4 | Password: p4
+
 ### To build a virtual machine with the P4 development tools.
 
 See the instructions [here](vm-ubuntu-24.04/README.md).
 
-### Accessing the VM
-
-+ There are two user accounts:
-  + Username: p4 | Password: p4 (Usage of this account is expected)
-  + Username: vagrant | Password: vagrant (There is no need to use this account)
-
 ### To install P4 development tools on an existing system
 
 There are instructions and scripts in another Github repository that can, starting from a freshly installed Ubuntu 20.04, 22.04, or 24.04 Linux system with enough RAM and free disk space, install all of the necessary P4 development tools to run the exercises in this repository.  You can find those instructions and scripts [here](https://github.com/jafingerhut/p4-guide/blob/master/bin/README-install-troubleshooting.md) (note that you must clone a copy of that entire repository in order for its install scripts to work).

vm-ubuntu-24.04/README.md

@@ -23,6 +23,12 @@ Linux virtual machine on a cloud service like Amazon Web Services,
 Google Cloud, or Microsoft Azure.  Or install Ubuntu Linux on a bare
 metal system.  Details of these other methods are not documented here.
 
+The `install.sh` script mentioned later will work on several supported
+versions of Ubuntu Linux, even if you do not install the Ubuntu GNOME
+desktop, but note that there are portions of the tutorials,
+e.g. `xterm` commands, and `wireshark`, that require a graphical
+desktop.
+
 All of the detailed instructions below require first installing
 [VirtualBox](https://virtualbox.org) on your host system.
 

vm-ubuntu-24.04/install.sh

@@ -22,13 +22,44 @@ THIS_SCRIPT_FILE_MAYBE_RELATIVE="$0"
 THIS_SCRIPT_DIR_MAYBE_RELATIVE="${THIS_SCRIPT_FILE_MAYBE_RELATIVE%/*}"
 THIS_SCRIPT_DIR_ABSOLUTE=`readlink -f "${THIS_SCRIPT_DIR_MAYBE_RELATIVE}"`
 
+print_usage() {
+    1>&2 echo "usage: $0 [ latest | <date> ]"
+    1>&2 echo ""
+    1>&2 echo "Dates supported:"
+    1>&2 echo "    2025-Jan-01"
+}
+
+if [ $# -eq 0 ]
+then
+    VERSION="2025-Jan-01"
+    echo "No version specified.  Defaulting to ${VERSION}"
+elif [ $# -eq 1 ]
+then
+    VERSION="$1"
+else
+    print_usage
+    exit 1
+fi
+
+case ${VERSION} in
+    2025-Jan-01)
+	# 2025-Jan-01 versions:
+	export INSTALL_BEHAVIORAL_MODEL_SOURCE_VERSION="7ca39eda3529347e4ba66f1976351b0087294bf8"
+	export INSTALL_PI_SOURCE_VERSION="2bb40f7ab800b91b26f3aed174bbbfc739a37ffa"
+	export INSTALL_P4C_SOURCE_VERSION="1dc0afae2207f4bb9f5ab45f105ed569cc1ac89b"
+	export INSTALL_PTF_SOURCE_VERSION="c554f83685186be4cfa9387eb5d6d700d2bbd7c0"
+	;;
+    latest)
+	echo "Using the latest version of all p4lang repository source code."
+	;;
+    *)
+	print_usage
+	exit 1
+	;;
+esac
+
 ${THIS_SCRIPT_DIR_ABSOLUTE}/user-bootstrap.sh
 
-# 2025-Jan-01 versions:
-export INSTALL_BEHAVIORAL_MODEL_SOURCE_VERSION="7ca39eda3529347e4ba66f1976351b0087294bf8"
-export INSTALL_PI_SOURCE_VERSION="2bb40f7ab800b91b26f3aed174bbbfc739a37ffa"
-export INSTALL_P4C_SOURCE_VERSION="1dc0afae2207f4bb9f5ab45f105ed569cc1ac89b"
-export INSTALL_PTF_SOURCE_VERSION="c554f83685186be4cfa9387eb5d6d700d2bbd7c0"
 
 ${THIS_SCRIPT_DIR_ABSOLUTE}/install-p4dev-v8.sh