MEGAcmd — Developer Guide

What this skill does

Instructions for BUILDING, DEBUGGING, TESTING, and CONTRIBUTING to the MEGAcmd repository. This skill is for developers who need to compile the project, set up the environment, or investigate the C++ source code.

> ⚠️ Do not activate this skill if the user just wants to USE MEGAcmd (upload, sync, backup). That is what the megacmd skill is for.

When to use

• The user wants to compile/install MEGAcmd from source code
• The user wants to set up a development environment (CMake, vcpkg)
• The user wants to run tests (unit or integration)
• The user wants to debug server/client issues
• The user wants to create packages (Debian, RPM, Arch, Synology, Windows)
• The user wants to contribute code or pull requests
• The user asks about the internal code architecture

When NOT to use

• The user wants to upload, download, sync, backup, or share — use megacmd
• The user wants to use the MEGA web interface
• The user wants to install MEGAcmd via ready-made packages (mega.nz/cmd)

Project Structure

MEGAcmd/
├── CMakeLists.txt              # Main build system (488 lines)
├── vcpkg.json                  # vcpkg-managed dependencies
├── src/
│   ├── megacmd_server_main.cpp # Server entry point
│   ├── megacmd.cpp/h           # MEGAcmd core
│   ├── megacmdexecuter.cpp/h   # Command executor
│   ├── megacmdutils.cpp/h      # Utilities
│   ├── megacmdcommonutils.cpp/h # Common utilities
│   ├── megacmdlogger.cpp/h     # Logging system
│   ├── megacmd_fuse.cpp/h      # FUSE support
│   ├── megacmdshell/           # Interactive shell
│   ├── client/                 # Client (mega-exec + mega-* wrappers)
│   │   ├── megacmd_client_main.cpp
│   │   ├── megacmdclient.cpp/h
│   │   ├── mega-*              # Bash wrappers (Linux/macOS)
│   │   └── win/mega-*.bat      # Windows wrappers
│   ├── comunicationsmanager.cpp/h  # IPC (File Sockets / Named Pipes)
│   ├── configurationmanager.cpp/h  # Configuration
│   ├── listeners.cpp/h         # SDK listeners
│   ├── sync_command.cpp/h      # Sync command
│   ├── sync_ignore.cpp/h       # Ignore patterns
│   └── sync_issues.cpp/h       # Sync issues
├── tests/
│   ├── unit/                   # Unit tests (C++)
│   ├── integration/            # Integration tests (C++)
│   └── *.sh, *.py              # Shell/Python tests
├── build/
│   ├── cmake/modules/          # CMake modules
│   ├── installer/              # Installers (NSIS, DMG, scripts)
│   ├── megacmd/                # Debian packages
│   └── templates/megacmd/      # RPM spec, PKGBUILD, DSC
├── contrib/
│   ├── docs/                   # Documentation (76 commands + guides)
│   ├── sanitizer/              # ASan, LSan, TSan suppressions
│   └── updater/                # Updater file lists
├── sdk/                        # MEGA SDK (git submodule)
└── jenkinsfile/                # CI/CD (Jenkins)

Build

Prerequisites

# Git + submodules
git clone https://github.com/meganz/MEGAcmd.git
cd MEGAcmd && git submodule update --init --recursive

Compile

# Debug
cmake -B build/build-cmake-Debug -DCMAKE_BUILD_TYPE=Debug
cmake --build build/build-cmake-Debug -j$(nproc)

# Release
cmake -B build/build-cmake-Release -DCMAKE_BUILD_TYPE=Release
cmake --build build/build-cmake-Release -j$(nproc)

# With tests
cmake -B build/build-cmake-Debug -DCMAKE_BUILD_TYPE=Debug -DENABLE_MEGACMD_TESTS=ON
cmake --build build/build-cmake-Debug -j$(nproc)

Install (Linux/macOS)

sudo cmake --install build/build-cmake-Release

Important Build Options

CMake Targets

Dependencies (vcpkg)

Required

pcre, cryptopp, curl (with zstd), icu, libsodium, sqlite3

Optional (vcpkg.json features)

Tests

# Unit tests
./build/build-cmake-Debug/tests/mega-cmd-tests-unit

# Integration tests (requires server running)
./build/build-cmake-Debug/tests/mega-cmd-tests-integration

# Python tests
python3 tests/megacmd_put_test.py
python3 tests/megacmd_get_test.py
python3 tests/megacmd_find_test.py

Docker

# Standard build
docker build -f build-with-docker/Dockerfile.cmake .

# Synology cross-compile
docker build -f build/SynologyNAS/dockerfile/synology-cross-build.dockerfile .

Debug

Logging

# Start server with debug
MEGAcmdServer --debug          # MEGAcmd=DEBUG, SDK=DEFAULT
MEGAcmdServer --debug-full     # MEGAcmd=DEBUG, SDK=DEBUG
MEGAcmdServer --verbose-full   # MEGAcmd=VERBOSE, SDK=VERBOSE

# Or via env var
MEGACMD_LOGLEVEL=FULLVERBOSE MEGAcmdServer
MEGACMD_JSON_LOGS=1 MEGAcmdServer  # JSON HTTP request logging

Log Files

• Linux/macOS: $HOME/.megaCmd/megacmdserver.log
• Windows: %LOCALAPPDATA%\MEGAcmd\.megaCmd\megacmdserver.log

Rotating Logger

Configure via megacmd.cfg in the log directory:

RotatingLogger:RotationType=Timestamp    # Timestamp | Numbered
RotatingLogger:CompressionType=Gzip      # Gzip | None
RotatingLogger:MaxFileMB=50
RotatingLogger:MaxFilesToKeep=20
RotatingLogger:MaxFileAgeSeconds=2592000 # 30 days
RotatingLogger:MaxMessageBusMB=512

Sanitizers

Files in contrib/sanitizer/:

• asan.suppressions — AddressSanitizer
• lsan.suppressions — LeakSanitizer
• tsan.suppressions — ThreadSanitizer

CI/CD

Jenkins

Jenkinsfiles in jenkinsfile/:

• Jenkinsfile_MR_linux, Jenkinsfile_MR_macos, Jenkinsfile_MR_windows
• Jenkinsfile_MR_linux_packages
• Branch_status/ — Release build pipelines

GitHub Issues

Template at .github/ISSUE_TEMPLATE/bug_report.yml

Packaging

Debian/APT

Files in build/megacmd/: control, rules, postinst, prerm, changelog

RPM (Fedora/SUSE)

build/templates/megacmd/megacmd.spec

Arch Linux

build/templates/megacmd/PKGBUILD

Windows (NSIS)

• build/installer_win.nsi — Installer script
• build/installer/ — Icons, banners, resources

macOS (DMG)

• build/installer_mac.sh — Installation script
• build/installer/Info.plist.in — Info.plist template

Synology NAS

• build/SynologyNAS/generate_pkg.sh — Generate SPK package
• build/SynologyNAS/toolkit/source/MEGAcmd/ — Installation scripts
• Docker cross-compile available

Generate Changelog

./build/generate_deb_changelog_entry.sh
./build/generate_rpm_changelog_entry.sh

Updater

Files in src/updater/ and contrib/updater/:

• MegaUpdater.cpp — Update logic
• fileswin.txt, fileswin64.txt, filesmacos.txt — File lists per platform

IPC (Client-Server Communication)

File Sockets (Unix/Linux/macOS)

Used between mega-exec and mega-cmd-server. Implementation in comunicationsmanagerfilesockets.cpp.

Named Pipes (Windows)

Used on Windows. Implementation in comunicationsmanagernamedpipes.cpp and megacmdshellcommunicationsnamedpipes.cpp.

TCP Socket (Python alternative)

src/client/python/mega-execports — connects on port 12300:

1. Connect to 127.0.0.1:12300
2. Send command as string
3. Receive 2 bytes (socketOutId)
4. Connect to 127.0.0.1:12300 + socketOutId
5. Receive 4 bytes (outCode) + output
6. Exit code = -outCode (if negative) or outCode

Advanced Settings

CMake Options

Options in build/cmake/modules/megacmd_options.cmake:

• USE_PCRE — PCRE for regular expressions (default: ON)
• USE_MEDIAINFO — MediaInfo (default: ON)
• USE_FREEIMAGE — FreeImage (default: ON)
• USE_FFMPEG — FFMPEG (default: ON)
• USE_LIBUV — libuv for WebDAV/FTP (default: ON)
• USE_PDFIUM — PDFium (default: ON)
• USE_READLINE — Readline (default: ON)
• ENABLE_MEGACMD_TESTS — Build tests (default: OFF)

Version

File build/version contains the current version: 2.5.2

Tips for Contributors

1. The codebase uses C++17
2. Main namespace: megacmd
3. MEGA SDK via submodule in sdk/
4. Style: 4 spaces, BSD 2-Clause header on all files
5. Always run unit tests before submitting a PR
6. To add a new command: edit megacmdexecuter.cpp (executecommand method)
7. To add a new flag: update getUsageStr() in megacmd.cpp and HelpFlags
8. Sanitizers are enabled by default in Debug builds