Bash-compatible SemVer Regex

A regular expression for use with bash that captures the fragments of the Semantic Versioning Specification. This repo also contains a short bash script that runs the regex against a set of example version numbers to check its validity.

This uses bash built-in regex handling, which uses POSIX regex. Think of it as an extension to the suggested regex FAQ entry for use in bash (which doesn't have a concept of non-capturing groups).

The Regex

Terse:

^(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-]+)*))?$

Human-Readable:

# Regex for a semver digit
D='0|[1-9][0-9]*'
# Regex for a semver pre-release word
PW='[0-9]*[a-zA-Z-][0-9a-zA-Z-]*'
# Regex for a semver build-metadata word
MW='[0-9a-zA-Z-]+'

if [[ "$INPUT" =~ ^($D)\.($D)\.($D)(-(($D|$PW)(\.($D|$PW))*))?(\+($MW(\.$MW)*))?$ ]]; then
    MAJOR="${BASH_REMATCH[1]}"
    MINOR="${BASH_REMATCH[2]:-""}"
    PATCH="${BASH_REMATCH[3]:-""}"
    PRE_RELEASE="${BASH_REMATCH[5]:-""}"
    BUILD_METADATA="${BASH_REMATCH[10]:-""}"
fi

The Capture Groups

The individual parts are captured as follows:

• Capture group 1: Major
• Capture group 2: Minor
• Capture group 3: Patch
• Capture group 5: Prerelease
• Capture group 10: Build metadata

Original Source

This repo came to life following a discussion in an issue in the semver repo on GitHub. See here.