Add initial codebase

shared.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+# shellcheck disable=SC2034
+set -euo pipefail
+
+# see: https://semver.org/spec/v2.0.0.html#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string
+pcre_semver='^(?P<major>0|[1-9]\d*)\.(?P<minor>0|[1-9]\d*)\.(?P<patch>0|[1-9]\d*)(?:-(?P<prerelease>(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+(?P<buildmetadata>[0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$'
+pcre_master_ver='^(?P<major>0|[1-9]\d*)\.(?P<minor>0|[1-9]\d*)\.(?P<patch>0|[1-9]\d*)$'
+pcre_allow_vprefix="^v{0,1}${pcre_master_ver:1}"
+pcre_old_calver='^(?P<major>0|[1-9]\d*)-0{0,1}(?P<minor>0|[0-9]\d*)-R(?P<patch>0|[1-9]\d*)$'
+
+##==----------------------------------------------------------------------------
+##  MacOS compatibility - for local testing
+
+export grep="grep"
+if [[ "$(uname)" == "Darwin" ]] ; then
+    export grep="ggrep"
+    if ! grep --version 1>/dev/null ; then
+        echo "🛑 GNU grep not installed, try brew install coreutils" 1>&2
+        exit 9
+    fi
+fi