MEGAcmd for Developer

Dev Tools

Build, debug, and contribute to the MEGAcmd project (C++/CMake/vcpkg). Use when the user needs to compile, set up a development environment, run tests, create packages, or understand MEGAcmd's internal architecture. Do NOT use for user operations (upload, sync, backup) — that is a different skill.

Install

openclaw skills install megacmd-developer

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

Flag	Description
`-DVCPKG_ROOT=/path`	Path to vcpkg (default: ../vcpkg)
`-DCMAKE_CXX_COMPILER_LAUNCHER=ccache`	Use ccache
`-DENABLE_MEGACMD_TESTS=ON`	Build tests
`-DCMAKE_INSTALL_PREFIX=/path`	Installation directory

CMake Targets

Target	Type	Description
`mega-cmd-server`	Executable	Server
`mega-cmd`	Executable	Interactive shell
`mega-exec`	Executable	Non-interactive client
`mega-cmd-updater`	Executable	Updater
`mega-cmd-tests-unit`	Executable	Unit tests
`mega-cmd-tests-integration`	Executable	Integration tests
`LMegaCmdCommonUtils`	Static library	Common utilities
`LMegacmdServer`	Static library	Server logic
`LMegacmdClient`	Static library	Client logic

Dependencies (vcpkg)

Required

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

Optional (vcpkg.json features)

Feature	Dependency	Activation
`use-openssl`	openssl	CMake
`use-mediainfo`	libmediainfo	CMake
`use-freeimage`	freeimage + jasper	CMake
`use-ffmpeg`	ffmpeg (avcodec, avformat, swresample, swscale)	CMake
`use-libuv`	libuv	CMake (WebDAV/FTP)
`use-pdfium`	pdfium	CMake
`use-readline`	readline	CMake
`megacmd-enable-tests`	gtest	`-DENABLE_MEGACMD_TESTS=ON`

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:

Connect to 127.0.0.1:12300
Send command as string
Receive 2 bytes (socketOutId)
Connect to 127.0.0.1:12300 + socketOutId
Receive 4 bytes (outCode) + output
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

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