hadd(1) General Commands Manual hadd(1)

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]
[-f[0-9] F[0_9]] [-fk FK] [-ff FF] [-f0 F0] [-f6 F6]

This program will add histograms, trees and other objects 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.

Append to the output
Skip corrupt or non-existent files, do not exit
Do not merge Trees
Re-optimize basket size when merging TTree
Explicitly set the verbosity level: 0 request no output, 99 is the
Parallelize the execution in multiple processes
Parallelize the execution in multiple processes in debug mode (Does
not delete partial files stored inside working directory)
Carry out the partial multiprocess execution in the specified
Open at most 'maxopenedfiles' at once (use 0 to request to use the
system maximum)
Resize the prefetching cache use to speed up I/O operations(use 0 to
Used with an argument provided, enables the corresponding experimental
feature for output trees
Force overwriting of output file.
Gives the ability to specify the compression level of the target file
(by default 4)
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)
The compression level use is the one specified in the first input
Do not compress the target file
Use compression level 6 (see TFile::SetCompressionSettings for the
supported range of values)
Target file
Source files