label-copy.sh

# Usage: bash label-copy.sh <source-repo> <destination-repo> <label-names>...
#
# Requirements: GitHub CLI, jq
#
# Example:
#   brew install gh jq
#   bash label-copy.sh owner/repo1 owner/repo2 "bug" "help wanted" "feature"
#

set -e

source_repo="${1?}"
destination_repo="${2?}"
shift 2

ascii_downcase() {
  tr 'A-Z' 'a-z'
}

selected=()
for label_name; do
  selected+=("$(ascii_downcase <<<"$label_name")")
done

post_args=()
IFS=$'\t'
gh api "repos/$source_repo/labels" | jq -r '.[] | [.name,.color,.description] | @tsv' | while read name color description; do
  for s in "${selected[@]}"; do
    if [ "$s" == "$(ascii_downcase <<<"$name")" ]; then
      gh api --silent "repos/$destination_repo/labels" -f name="$name" -f color="$color" -f description="$description"
    fi
  done
done