Extract the release tag (version) of the latest release of a given GitHub repository, potentially for specific OS, architecture and package type

getGitHubLatestRelease.sh

#!/bin/bash

git_repo="containernetworking/plugins"
os="linux"
arch="amd64"
pack="tgz"

if [ -z "$1" -o "$1" = "-h" -o "$1" = "--help" ]
then
        echo
        echo "Usage: $0 <github-repo> [[[<os>] <arch>] <pack>]"
        echo " - <github-repo>: GitHub repo, for instance containernetworking/plugins"
        echo " - <os>:          Operating System, for instance linux, windows, darwin"
        echo " - <arch>:        Architecture, for instance amd64, arm, arm64, ppc64le, s390"
        echo " - <pack>:        Type of package, for instance tgz, zip>"
        echo
        exit
fi

git_repo="$1"

if [ ! -z "$2" ]
then
        os="$2"
fi

if [ ! -z "$3" ]
then
        arch="$3"
fi

if [ ! -z "$4" ]
then
        pack="$4"
fi

curl --silent "https://api.github.com/repos/${git_repo}/releases/latest" | grep "browser_download_url" | grep "${os}-${arch}" | grep "\.${pack}\"$" | sed -n -e "s|^.*/\([a-z0-9\-]*[0-9]\+.[0-9]\+.[0-9]\)/.*$|\1|p"

# Reporting
echo " - GitHub repo:           ${git_repo} (https://github.com/${git_repo}/releases)"
echo " - OS:                    ${os}"
echo " - Architecture:  ${arch}"
echo " - Package type:  ${pack}"