Generate markdown CHANGELOG from git-log with included comparison links

generate_changelog.sh

#!/bin/bash

generate_changelog()
{
    github_user="user"
    github_project_name="project"
    first_commit=$(git rev-list --max-parents=0 HEAD)
    git for-each-ref --sort=-refname --format="## [%(refname:short)] - %(taggerdate:short) &(newline)*** &(newline)- %(subject) %(body)" refs/tags > CHANGELOG.md
    gsed -i '''s/\&(newline)/\n/' CHANGELOG.md # replace first instance
    gsed -i '''s/\&(newline)/\n/' CHANGELOG.md # replace second instance
    echo -e "\n" >> CHANGELOG.md
    for curr_tag in $(git tag -l --sort=-v:refname)
    do
        prev_tag=$(git describe --abbrev=0 ${curr_tag}^)
        if [ -z "${prev_tag}" ]
        then
            prev_tag=${first_commit}
        fi
        echo "[${curr_tag}]: https://github.com/${github_user}/${github_project_name}/compare/${prev_tag}..${curr_tag}" >> CHANGELOG.md
    done
}