hadd(1)

SYNOPSIS
usage: hadd [-a A] [-k K] [-T T] [-O O] [-v V] [-j J] [-dbg DBG] [-d D] [-n N]
            [-cachesize CACHESIZE]
            [-experimental-io-features EXPERIMENTAL_IO_FEATURES] [-f F]
            [-fk FK] [-ff FF] [-f0 F0] [-f6 F6]
            TARGET SOURCES

DESCRIPTION
This program will add histograms from a list of root files and write them to a target root file. The target file is newly created and must not exist, or if -f ("force") is given, must not be one of the source files.

OPTIONS

-a  Append to the output

-k  Skip corrupt or non-existent files, do not exit

-T  Do not merge Trees

-O  Re-optimize basket size when merging TTree

-v  Explicitly set the verbosity level: 0 request no output, 99 is the default

-j  Parallelize the execution in multiple processes

-dbg
    Parallelize the execution in multiple processes in debug mode (Does not delete partial files stored inside working directory)

-d  Carry out the partial multiprocess execution in the specified directory

-n  Open at most 'maxopenedfiles' at once (use 0 to request to use the system maximum)

-cachesize
    Resize the prefetching cache use to speed up I/O operations(use 0 to disable)

-experimental-io-features
    Used with an argument provided, enables the corresponding experimental feature for output trees

-f  Gives the ability to specify the compression level of the target file(by default 4)

-fk Sets the target file to contain the baskets with the same compression

    as the input files (unless -O is specified). Compresses the meta data

    using the compression level specified in the first input or the

    compression setting after fk (for example 206 when using -fk206)

-ff The compression level use is the one specified in the first input

-f0 Do not compress the target file

-f6 Use compression level 6. (See TFile::SetCompressionSettings for the support range of value.)

TARGET
    Target file

SOURCES
    Source files