Semver versioning with git tags & npm version

version.sh

#!/bin/sh

# Convenience script for versioning
# Pass a semver-formatted version number to this script such as `npm version 2.1.0`.
#
# You'll get:
# 1) git tag such as v2.1.0
# 2) new version to `package.json`

npm version $1

Here is a way to validate the first arguments presence:

version="$1"

if [ -z "$version" ]; then
    echo "First argument should be a semver-formatted version number such as '2.1.0'."
    exit 1
fi

npm version "$version"