hadd(1) General Commands Manual hadd(1)

usage: hadd [-a] [-f] [-f[0-9]] [-fk] [-ff] [-k] [-L] [-Ltype] [-O] [-T]
[-v V] [-j J] [-dbg] [-d D] [-n N] [-cachesize CACHESIZE]
[-experimental-io-features EXPERIMENTAL_IO_FEATURES]
TARGET SOURCES

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
Force overwriting of output file
Gives the ability to specify the compression algorithm i and level j
of the target file, by passing the number i*100 + j, e.g. -f505. The
last digit (j) can be set from 0 = uncompressed to 9 = highly
compressed. The first digit (i) is 1 for ZLIB, 2 for LZMA, 4 for LZ4
and 5 for ZSTD. Recommended numbers are 101 (ZLIB), 207 (LZMA), 404
(LZ4), 505 (ZSTD). The default value for this flag is 101
(kDefaultZLIB). See ROOT::RCompressionSetting and TFile::TFile
documentation for more details.
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
Skip corrupt or non-existent files, do not exit
Read the list of objects from FILE and either only merge or skip those
objects depending on the value of "-Ltype". FILE must contain one
object name per line, which cannot contain whitespaces or '/'. You can
also pass TDirectory names, which apply to the entire directory
content. Lines beginning with '#' are ignored. If this flag is passed,
"-Ltype" MUST be passed as well.
Sets the type of operation performed on the objects listed in FILE
given with the "-L" flag. "SkipListed" will skip all the listed
objects; "OnlyListed" will only merge those objects. If this flag is
passed, "-L" must be passed as well.
Re-optimize basket size when merging TTree
Do not merge Trees
Explicitly set the verbosity level: 0 request no output, 99 is the
default
Parallelize the execution in 'J' processes. If the number of processes
is not specified, use the system maximum.
Enable verbosity. If -j was specified, do not not delete partial files
stored inside working directory.
Carry out the partial multiprocess execution in the specified
directory
Open at most 'N' files 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
disable)
Used with an argument provided, enables the corresponding experimental
feature for output trees. See ROOT::Experimental::EIOFeatures
Target file
Source files