Migrate from Bitbucket to GitHub

migrate-bitbucket-to-github.sh

#!/usr/bin/env bash
set -euo pipefail

# =============================================================================
# migrate-bitbucket-to-github.sh
#
# Batch-migrates all private Bitbucket repositories to GitHub.
# - Repos are created as private on GitHub
# - The default branch is renamed from `master` to `main` (if applicable)
# - Local clones are cleaned up immediately after each push
# - A temporary working directory is used and removed on exit
#
# Prerequisites:
#   - `git`, `curl`, and `jq` must be installed
#   - Bitbucket API Token with "Repository: Read" scope
#     (create at bitbucket.org → Personal Bitbucket settings → API tokens)
#   - Bitbucket account email address
#     (find at bitbucket.org → Personal Bitbucket settings → Email aliases)
#   - GitHub Personal Access Token (classic) with "repo" scope
#     (create at github.com → Settings → Developer settings → Personal access tokens)
#
# Usage:
#   chmod +x migrate-bitbucket-to-github.sh
#   ./migrate-bitbucket-to-github.sh
# =============================================================================

# === Configuration ===
BITBUCKET_USER=""             # Your Bitbucket username (not email)
BITBUCKET_EMAIL=""            # Your Atlassian account email (for REST API auth)
BITBUCKET_API_TOKEN=""        # Your Bitbucket API token

GITHUB_USER=""       # Your GitHub username (not email)
GITHUB_TOKEN=""      # GitHub Personal Access Token (classic) with "repo" scope

# === Temporary working directory ===
# All bare clones are created here and cleaned up after each repo.
# The trap ensures the directory is removed on exit, even on error.
WORKDIR=$(mktemp -d)
cd "$WORKDIR"
trap "rm -rf '$WORKDIR'" EXIT

# === Fetch all Bitbucket repos ===
echo "Fetching all Bitbucket repos for user: $BITBUCKET_USER ..."

# REST API authentication uses email + API token (Basic Auth).
# Note: If you have more than 100 repos, pagination needs to be implemented.
repos=$(curl -s -u "$BITBUCKET_EMAIL:$BITBUCKET_API_TOKEN" \
    "https://api.bitbucket.org/2.0/repositories/$BITBUCKET_USER?pagelen=100" \
    | jq -r '.values[].name')

echo "Found repos:"
echo "$repos"

# === For each repo: create on GitHub, mirror, rename branch, push ===
for repo in $repos; do
  echo "--------------------------------------------"
  echo "Processing repo: $repo"

  # Create the repo on GitHub as private.
  # HTTP 201 = created, 422 = already exists (both are fine).
  response=$(curl -s -o /dev/null -w "%{http_code}" -X POST "https://api.github.com/user/repos" \
    -H "Accept: application/vnd.github+json" \
    -H "Authorization: Bearer $GITHUB_TOKEN" \
    -H "X-GitHub-Api-Version: 2022-11-28" \
    -d "{\"name\":\"$repo\",\"private\":true}")

  if [[ "$response" == "201" ]]; then
    echo "Created new repo on GitHub: $repo"
  elif [[ "$response" == "422" ]]; then
    echo "Repo already exists on GitHub: $repo"
  else
    echo "Failed to create repo on GitHub: HTTP $response — skipping."
    continue
  fi

  # Clone a bare mirror from Bitbucket.
  # Git authentication uses the static username x-bitbucket-api-token-auth + API token.
  echo "Cloning mirror from Bitbucket..."
  git clone --mirror \
    "https://x-bitbucket-api-token-auth:$BITBUCKET_API_TOKEN@bitbucket.org/$BITBUCKET_USER/$repo.git" \
    || { echo "Clone failed, skipping $repo."; continue; }

  cd "$repo.git"

  # Rename master to main if master exists.
  # git symbolic-ref updates HEAD so GitHub picks up main as the default branch.
  if git show-ref --verify --quiet refs/heads/master; then
    echo "Renaming master → main..."
    git branch -m master main
    git symbolic-ref HEAD refs/heads/main
    echo "Renamed master to main."
  else
    echo "No master branch found, skipping rename."
  fi

  # Push all refs to GitHub.
  echo "Pushing mirror to GitHub..."
  git remote set-url origin \
    "https://$GITHUB_USER:$GITHUB_TOKEN@github.com/$GITHUB_USER/$repo.git"
  git push --mirror

  cd ..

  # Remove the local bare clone immediately after pushing.
  echo "Cleaning up local clone..."
  rm -rf "$repo.git"

  echo "Done: $repo"
done

echo "============================================"
echo "All repos migrated!"