UDU is an extremely fast, cross-platform tool for summarizing file and directory sizes by recursively scanning directories using a parallel traversal engine implemented with OpenMP, making it significantly faster than traditional tools on multi-core systems.

See Benchmarks for performance comparisons.

UDU uses a parallel directory traversal engine to compute file and directory sizes efficiently. The master thread starts at the given path and spawns worker threads for each subdirectory. Each worker recursively enumerates its directory, computing file sizes directly and spawning further threads for nested directories. At the end the results propagate back to the master thread for aggregation.

            
                     +----------------+
                     | MASTER THREAD  |
                     |     <path>     |
                     +--------+-------+
                              |
                  -------------------------
                  |           |           |
            +-----v-----+ +---v-----+ +---v-----+
            | FILE      | | DIR A   | | DIR B   |
            | (compute) | | (spawn) | | (spawn) |
            +-----------+ +---------+ +---------+
                              |           |
                      -------------------------
                      |           |           |
                  +---v---+   +---v---+   +---v---+
                  | FILE  |   | DIR C |   | DIR D |
                  +-------+   +-------+   +-------+
                              |           |
                         +----v-----+ +---v------+
                         | WORKER C | | WORKER D |
                         +----------+ +----------+
                              |           |
                             ...         ...
            

The C implementation provides the best performance when built with OpenMP, requiring a modern C compiler such as GCC 9 or later, Clang 14 or later, or MSVC 17 or later, along with CMake 3.15 or later and OpenMP 3.1 or later (optional but recommended).

Note on Windows: MSVC only supports OpenMP 2.0, which doesn't meet the requirements for building this program. We recommend using GCC or Clang through MSYS2 instead, though alternative Windows development environments like Cygwin also provide modern compiler toolchains with full OpenMP support.

Clone the repository and build using these commands:

git clone --depth=1 https://github.com/gnualmalki/udu.git
cd udu
cmake -B build -DCMAKE_BUILD_TYPE=Release -DENABLE_OPENMP=ON -DENABLE_LTO=ON
cmake --build build
cmake --install build  # may require administrator privileges

After installing MSYS2, open the UCRT64 terminal and install the required packages using pacman -S mingw-w64-ucrt-x86_64-gcc mingw-w64-ucrt-x86_64-cmake, then clone the repository and build:

git clone --depth=1 https://github.com/gnualmalki/udu.git
cd udu
cmake -B build -DCMAKE_BUILD_TYPE=Release -DENABLE_OPENMP=ON -DENABLE_LTO=ON
cmake --build build
cmake --install build  # may require administrator privileges

udu <path>... [OPTIONS]...

  -a, --apparent-size            display apparent sizes rather than device usage
  -v, --verbose                  enable verbose output
  -q, --quiet                    enable quiet output (default)
  -X <name>, --exclude=<name>    exclude file or directory
  -h, --help                     display this help and exit
      --version                  display version information and exit

This program is distributed under the GNU General Public License Version 3, see the LICENSE file for details.

• Thanks to OpenMP specification and its implementations by GCC and LLVM for making FOSS high-performance parallel computing possible.
• Thanks to xxHash for fast hashing.