A POSIX Compliant SemVer Parser in Pure Bash

example--parse-semver-with-bash.sh

#!/usr/bin/env bash

VERSION="${1#[vV]}"
VERSION_MAJOR="${VERSION%%.*}"
VERSION_MINOR_PATCH="${VERSION#*.}"
VERSION_MINOR="${VERSION_MINOR_PATCH%%.*}"
VERSION_PATCH_PRE_RELEASE="${VERSION_MINOR_PATCH#*.}"
VERSION_PATCH="${VERSION_PATCH_PRE_RELEASE%%[-+]*}"
VERSION_PRE_RELEASE=""

case "$VERSION" in
  *-*)
    VERSION_PRE_RELEASE="${VERSION#*-}"
    VERSION_PRE_RELEASE="${VERSION_PRE_RELEASE%%+*}"
    ;;
esac

echo "Version: ${VERSION}"
echo "Version [major]: ${VERSION_MAJOR}"
echo "Version [minor]: ${VERSION_MINOR}"
echo "Version [patch]: ${VERSION_PATCH}"
echo "Version [pre-release]: ${VERSION_PRE_RELEASE}"

Just a note that this does not correctly parse out minor version out of 2.0.0-rc.2

€ ./exmple--parse-semver-with-bash.sh 2.0.0-rc.2   
Version: 2.0.0-rc.2
Version [major]: 2
Version [minor]: 0.0-rc
Version [patch]: 2

https://semver.org/spec/v2.0.0-rc.2.html

@mman : Nice catch. When I built this for a small project, I never used pre-releases. I've updated the logic to account for per-releases as well as remove any potential metadata that could exist.

@andyfeller : If you're still using this logic anywhere, you may want to update it ;)

Well, actually there is still one bug in the logic. The last test I ran locally, the rc is still a part of the patch release. I need to account for that.

bitmvr@bitmvr-macbook-00 tmp % ./version-parse.sh 1.2.3-rc-4.5.6 
Version: 1.2.3-rc-4.5.6
Version [major]: 1
Version [minor]: 2
Version [patch]: 3-rc
Version [pre-release]: rc-4.5.6

Okay, I've patched it. I will add comments later around what's happening where as parameter expansion in Bash can be confusing.

@bitmvr Cool thanks a lot, I think that as much as SemVer is popular, we actually (if I am not mistaken) miss generally well available installed everywhere typ of tool to actually parse semver, to use in GitHub actions, and build scripts, etc. so your script is actually very handy :-)