.TH hadd 1 
.SH SYNOPSIS
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

.SH DESCRIPTION
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.
.SH OPTIONS
.IP -a
Append to the output
.IP -f
Force overwriting of output file
.IP -f[0-9]
Gives the ability to specify the compression algorithm i and level j
.IP
of the target file, by passing the number i*100 + j, e.g. -f505. The
.IP
last digit (j) can be set from 0 = uncompressed to 9 = highly
.IP
compressed. The first digit (i) is 1 for ZLIB, 2 for LZMA, 4 for LZ4
.IP
and 5 for ZSTD. Recommended numbers are 101 (ZLIB), 207 (LZMA), 404
.IP
(LZ4), 505 (ZSTD). The default value for this flag is 101
.IP
(kDefaultZLIB). See ROOT::RCompressionSetting and TFile::TFile
.IP
documentation for more details.
.IP -fk
Sets the target file to contain the baskets with the same compression
.IP
as the input files (unless -O is specified). Compresses the meta data
.IP
using the compression level specified in the first input or the
.IP
compression setting after fk (for example 206 when using -fk206)
.IP -ff
The compression level use is the one specified in the first input
.IP -k
Skip corrupt or non-existent files, do not exit
.IP -L
Read the list of objects from FILE and either only merge or skip those
.IP
objects depending on the value of "-Ltype". FILE must contain one
.IP
object name per line, which cannot contain whitespaces or '/'. You can
.IP
also pass TDirectory names, which apply to the entire directory
.IP
content. Lines beginning with '#' are ignored. If this flag is passed,
.IP
"-Ltype" MUST be passed as well.
.IP -Ltype
Sets the type of operation performed on the objects listed in FILE
.IP
given with the "-L" flag. "SkipListed" will skip all the listed
.IP
objects; "OnlyListed" will only merge those objects. If this flag is
.IP
passed, "-L" must be passed as well.
.IP -O
Re-optimize basket size when merging TTree
.IP -T
Do not merge Trees
.IP -v
Explicitly set the verbosity level: 0 request no output, 99 is the
.IP
default
.IP -j
Parallelize the execution in 'J' processes. If the number of processes
.IP
is not specified, use the system maximum.
.IP -dbg
Enable verbosity. If -j was specified, do not not delete partial files
.IP
stored inside working directory.
.IP -d
Carry out the partial multiprocess execution in the specified
.IP
directory
.IP -n
Open at most 'N' files at once (use 0 to request to use the system
.IP
maximum)
.IP -cachesize
Resize the prefetching cache use to speed up I/O operations (use 0 to
.IP
disable)
.IP -experimental-io-features
Used with an argument provided, enables the corresponding experimental
.IP
feature for output trees. See ROOT::Experimental::EIOFeatures
.IP TARGET
Target file
.IP SOURCES
Source files