Script to generate authors files by version for Bibtex (#82)

* Script to generate authors files by version for Bibtex
* Add example usage
* Generated v1.0.0 authors reference file
* Update note at the top of the top of generated files
* Regenerate authors-v1.0.0.md
* Use sort -u and check arg only once
* make shellcheck happy
* conditional bracket consistency

---------
Co-authored-by: Christian Hernandez <[email protected]>

Signed-off-by: Scott Rigby <[email protected]>

Author: scottrigby

reference/authors-v1.0.0.md

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+# v1.0.0 Authors
+
+⚠️ Do not edit this file directly.
+It is [auto-generated](../scripts/authors-by-version.sh) from Git history of source files in this repo.
+
+ℹ️ Note this is purely a convenience for referencing in academic papers.
+See the full Git history of specific files for additional context.
+
+## Authors List
+
+- Andrew Block <[email protected]>
+- Brian Fox <[email protected]>
+- Brian Fox <[email protected]>
+- Brice Fernandes <[email protected]>
+- Cansu Kavılı Örnek <[email protected]>
+- Carlos Santana <[email protected]>
+- Carlos Santana <[email protected]>
+- Chris Sanders <[email protected]>
+- Chris Short <[email protected]>
+- Christian Hernandez <[email protected]>
+- Cornelia Davis <[email protected]>
+- Dan Garfield <[email protected]>
+- Daniel Warner <[email protected]>
+- Florian Heubeck <[email protected]>
+- Ishita Sequeira <[email protected]>
+- Jesse Butler <[email protected]>
+- John Pitman <[email protected]>
+- Kevin Bowersox <[email protected]>
+- Kingdon Barrett <[email protected]>
+- Leonardo Murillo <[email protected]>
+- Leonardo Murillo <[email protected]>
+- Lloyd Chang <[email protected]>
+- Lothar Schulz <[email protected]>
+- Michael Bridgen <[email protected]>
+- Moshe Immerman <[email protected]>
+- Nicholas Thomson <[email protected]>
+- Nicholas Thomson <[email protected]>
+- Piotr <[email protected]>
+- Regina Scott <[email protected]>
+- Robert A Ficcaglia <[email protected]>
+- Roberth Strand <[email protected]>
+- Schlomo Schapiro <[email protected]>
+- Scott Rigby <[email protected]>
+- Sean Sundberg <[email protected]>
+- Shoubhik Bose <[email protected]>
+- Timothy Lin <[email protected]>
+- Toni Menzel <[email protected]>
+- William Caban <[email protected]>
+- William Chia <[email protected]>
+- lloydchang <[email protected]>

scripts/authors-by-version.sh

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+#!/bin/bash
+
+# Example usage:
+# mkdir -p reference
+# for VERSION in v1.0.0 HEAD; do
+#   ./scripts/authors-by-version.sh $VERSION > reference/authors-$VERSION.md
+# done
+
+# Authors, comitters, co-authors
+get_authors() {
+    local git_tag="$1"
+    shift  # Shift arguments to get the files
+    local files="$*"
+    # shellcheck disable=SC2086
+    git --no-pager log "$git_tag" -- $files | \
+        sed -n -e 's/^Author: //p' -e 's/^Committer: //p' -e 's/^.*Co-authored-by: //p' | \
+        sort -u | sed -e 's/^/- /'
+}
+
+# Ensure tag argument is provided
+GIT_TAG=$1
+
+if [[ -z ${GIT_TAG} ]]; then
+    echo "Usage: $0 <git-tag>"
+    exit 1
+fi
+
+if [ ! "$(git tag -l "$GIT_TAG")" ] && [ ! "$GIT_TAG" == "HEAD" ]; then
+    echo "<git-tag> '$GIT_TAG' does not exist"
+    exit 1
+fi
+
+# Check if translations
+git show "$GIT_TAG":i18n > /dev/null 2>&1 && i18n=true || i18n=false
+
+
+# Output
+cat <<EOF
+# $GIT_TAG Authors
+
+⚠️ Do not edit this file directly.
+It is [auto-generated](../scripts/authors-by-version.sh) from Git history of source files in this repo.
+
+ℹ️ Note this is purely a convenience for referencing in academic papers.
+See the full Git history of specific files for additional context.
+
+EOF
+
+# If translations exist, output a note about language and translations
+if [[ $i18n = true ]]; then
+    cat <<EOF
+## Language and Translations
+
+The GitOps Principles and Glossary are [authored](#authors-list) in English.
+See farther below for a list of [translators](#translators-list) by language.
+
+EOF
+fi
+
+# Get authors list
+AUTHORS=$(get_authors "$GIT_TAG" "PRINCIPLES.md GLOSSARY.md")
+
+# Append to output
+cat <<EOF
+## Authors List
+
+$AUTHORS
+EOF
+
+# If translations exist, append translator lists
+if [[ $i18n = true ]]; then
+    # Get translator lists
+    DE=$(get_authors "$GIT_TAG" i18n/*_de.md)
+    ES=$(get_authors "$GIT_TAG" i18n/*_es.md)
+    PT=$(get_authors "$GIT_TAG" i18n/*_pt.md)
+    FR=$(get_authors "$GIT_TAG" i18n/*_fr.md)
+
+    # Append to output
+    cat <<EOF
+
+## Translators List
+
+### German
+
+$DE
+
+### Spanish
+
+$ES
+
+### Portuguese
+
+$PT
+
+### French
+
+$FR
+EOF
+fi