Bash script for checking a semantic version

check_semver.sh

#!/usr/bin/env bash
# https://gist.github.com/rverst/1f0b97da3cbeb7d93f4986df6e8e5695

function chsv_check_version() {
  if [[ $1 =~ ^(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)(-((0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*)(\.(0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*))*))?(\+([0-9a-zA-Z-]+(\.[0-9a-zA-Z-]+)*))?$ ]]; then
    echo "$1"
  else
    echo ""
  fi
}

function chsv_check_version_ex() {
  if [[ $1 =~ ^v.+$ ]]; then
    chsv_check_version "${1:1}"
  else
    chsv_check_version "${1}"
  fi
}

function chsv_print_usage() {
  echo
  echo "Usage: check_semver.sh [OPTIONS] VERSION"
  echo
  echo "A script to check a version on compliance to Semantic Versioning 2.0.0. (https://semver.org/)"
  echo
  echo "Options:"
  echo "  -v        Verbose output, prints errors and echos the raw version on success"
  echo "  -t        Run tests"
  echo "  -h        Print usage"
  echo
  echo "Version:"
  echo "The version to test, e.g. '1.0.0'. The version can be prefixed with a 'v', in case of verbose is enabled,"
  echo "the prefixed 'v' will be stripped from the output."
  echo
  echo
}

function chsv_test_valid() {
  local valid=(0.0.4 1.2.3 10.20.30 1.1.2-prerelease+meta 1.1.2+meta 1.1.2+meta-valid 1.0.0-alpha 1.0.0-beta 1.0.0-alpha.beta 1.0.0-alpha.beta.1 1.0.0-alpha.1 1.0.0-alpha0.valid 1.0.0-alpha.0valid 1.0.0-alpha-a.b-c-somethinglong+build.1-aef.1-its-okay 1.0.0-rc.1+build.1 2.0.0-rc.1+build.123 1.2.3-beta 10.2.3-DEV-SNAPSHOT 1.2.3-SNAPSHOT-123 1.0.0 2.0.0 1.1.7 2.0.0+build.1848 2.0.1-alpha.1227 1.0.0-alpha+beta 1.2.3----RC-SNAPSHOT.12.9.1--.12+788 1.2.3----R-S.12.9.1--.12+meta 1.2.3----RC-SNAPSHOT.12.9.1--.12 1.0.0+0.build.1-rc.10000aaa-kk-0.1 99999999999999999999999.999999999999999999.99999999999999999 1.0.0-0A.is.legal)
  for i in "${valid[@]}"; do
    if [[ ! $(chsv_check_version ${i}) ]]; then
      if [[ $verbose -eq 1 ]]; then
        echo "error in chsv_test_valid, '${i}' is a valid semantic version" >&2
      fi
      exit 1
    fi
  done
  if [[ $verbose -eq 1 ]]; then
    echo "chsv_test_valid   - OK"
  fi
}

function chsv_test_invalid() {
  local invalid=(1 1.2 1.2.3-0123 1.2.3-0123.0123 1.1.2+.123 +invalid -invalid -invalid+invalid -invalid.01 alpha alpha.beta alpha.beta.1 alpha.1 alpha+beta alpha_beta alpha. alpha.. beta 1.0.0-alpha_beta -alpha. 1.0.0-alpha.. 1.0.0-alpha..1 1.0.0-alpha...1 1.0.0-alpha....1 1.0.0-alpha.....1 1.0.0-alpha......1 1.0.0-alpha.......1 01.1.1 1.01.1 1.1.01 1.2 1.2.3.DEV 1.2-SNAPSHOT 1.2.31.2.3----RC-SNAPSHOT.12.09.1--..12+788 1.2-RC-SNAPSHOT -1.0.3-gamma+b7718 +justmeta 9.8.7+meta+meta  9.8.7-whatever+meta+meta 99999999999999999999999.999999999999999999.99999999999999999----RC-SNAPSHOT.12.09.1--------------------------------..12)
  for i in "${invalid[@]}"; do
    if [[ $(chsv_check_version ${i}) ]]; then
      if [[ $verbose -eq 1 ]]; then
        echo "error in chsv_test_invalid, '${i}' is a valid semantic version" >&2
      fi
      exit 1
    fi
  done
  if [[ $verbose -eq 1 ]]; then
    echo "chsv_test_invalid - OK"
  fi
}

function chsv_main() {
  test=0
  verbose=0
  version="${@: -1}"

  while getopts ":vt" opt; do
    case $opt in
      t) test=1
      ;;
      v) verbose=1
      ;;
      \?) echo "Invalid option -$OPTARG" >&2; echo; chsv_print_usage; exit 1
      ;;
    esac
  done

  if [[ $test -eq 1 ]]; then
    chsv_test_valid
    chsv_test_invalid
    exit 0
  fi

  semver=$(chsv_check_version_ex "$version")

  if [[ ! "$semver" ]]; then
    if [[ $verbose -eq 1 ]]; then
      echo "'$version' is not a valid semantic version"
    fi
    exit 2
  fi

  if [[ $verbose -eq 1 ]]; then
    echo "$semver"
  fi
  exit 0
}

chsv_main "$@"

Well, bash is also a shell. If you mean the bourne-shell ('sh'), that won't work, because AFAIK there is no regex implemented. This script is designed for bash and will probably not work in other shells (in sh, zsh and fish definitely not).

yeah, and it is so.