diff --git a/scripts/code_manager_config_version.rb b/scripts/config_version-r10k.rb
similarity index 100%
rename from scripts/code_manager_config_version.rb
rename to scripts/config_version-r10k.rb
diff --git a/scripts/config_version.rb b/scripts/config_version-rugged.rb
similarity index 100%
rename from scripts/config_version.rb
rename to scripts/config_version-rugged.rb
diff --git a/scripts/config_version.sh b/scripts/config_version.sh
index 8dd8086..bdbc511 100755
--- a/scripts/config_version.sh
+++ b/scripts/config_version.sh
@@ -1,12 +1,35 @@
-#!/bin/bash
-if [ -e $1/$2/.r10k-deploy.json ]
-then
-  /opt/puppetlabs/puppet/bin/ruby $1/$2/scripts/code_manager_config_version.rb $1 $2
-elif [ -e /opt/puppetlabs/server/pe_version ]
-then
-  /opt/puppetlabs/puppet/bin/ruby $1/$2/scripts/config_version.rb $1 $2
-else
-  /usr/bin/git --version > /dev/null 2>&1 &&
-  /usr/bin/git --git-dir $1/$2/.git rev-parse HEAD ||
-  date +%s
+#!/bin/sh
+
+# Usage
+if [ $# -ne 2 -o ! -d "$1" -o ! -d "$1/$2" ]; then
+  echo "usage: $0 <environmentpath> <environment>" >&2
+  exit 1
+fi
+
+# For portability, identify a preferred ruby executable to use
+ruby() {
+  [ -x /opt/puppetlabs/puppet/bin/ruby ] \
+    && /opt/puppetlabs/puppet/bin/ruby "$@" \
+    || /usr/bin/env ruby "$@"
+}
+
+# Determine how best to calculate a config_version
+if [ -e $1/$2/.r10k-deploy.json ]; then
+  # The environment was deployed using r10k. We will calculate the config
+  # version using the r10k data.
+  ruby $1/$2/scripts/config_version-r10k.rb $1 $2
+
+elif [ -e /opt/puppetlabs/server/pe_version ]; then
+  # This is a Puppet Enterprise system and we can rely on the rugged ruby gem
+  # being available.
+  ruby $1/$2/scripts/config_version-rugged.rb $1 $2
+
+elif type git >/dev/null; then
+  # The git command is available.
+  git --git-dir $1/$2/.git rev-parse HEAD
+
+else
+  # Nothing else available; just use the date.
+  date +%s
+
 fi