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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTE | SEE ALSO | COLOPHON |
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PMLOGCOMPRESS(1) General Commands Manual PMLOGCOMPRESS(1)
pmlogcompress, pmlogdecompress - compress and decompress PCP
archive files
pmlogcompress [-NV?] [-A arg] [-c proglist] [-f prog] [-l limit]
[-o type] [-Z min] archive ...
pmlogdecompress [-NV?] [-t dir] archive ...
pmlogcompress and pmlogdecompress support the compression and
decompression of the files that make up a Performance Co-Pilot
(PCP) archive; refer to LOGARCHIVE(5) for an explanation of the
various files that are components of a PCP archive.
The archive arguments may be either the name of a single file in a
PCP archive or the basename of a PCP archive, as in the style
generated by pmlogbasename(1). In the former case, pmlogcompress
will compress (or pmlogdecompress will decompress) just that file,
but in the latter case pmlogcompress will attempt to compress (or
for pmlogdecompress to decompress) all the files that are part of
the associated PCP archive.
For decompression the suffix of the name of each file associated
with archive determines the decompression tool to be used.
The available command line options are:
-A arg, --arg=arg
arg is used as an argument to the compression program; most
likely useful with the -f option so that the choice of
compression program is deterministic.
The processing of arg is not sophisticated, so embedded shell
variables, escape characters, shell ``glob'' characters and
white space should be avoided.
Multiple -A options are allowed and all the arg arguments
will be used.
-c proglist, --command=proglist
Depending on other command line options, and the availability
of installed compression programs, the choice if program when
compressing may vary. The -c option allows a list of
compression programs to be provided, either with multiple -c
options and/or by separating program names in proglist by a
colon, in the style of the shell's $PATH notation.
The default value for proglist is zstd:xz:bzip2:gzip.
-f prog, --use=prog
If only one program is to be considered for compression then
this may be specified using the -f option. The effect is the
same as if only one -c option was used, and proglist
contained exactly one program name, namely prog.
-l limit, --lower-limit=limit
When compressing, do not consider files smaller than limit
(bytes).
The default value for limit is 4096.
-N, --show-me
Do nothing, but show what commands would have been executed.
-o type, --optimize=type
When compressing the -o option will try to pick the
compression program from proglist (see the -c option above)
that does the ``best'' job, where type may be space to choose
the compression program that produces the smallest output
file, or time to choose the compression program that uses the
least CPU time.
If archive is an archive basename then the largest of the
files that are part of the associated PCP archive is selected
for the test, else archive will be used for the test.
Use of this option means each of the selected archive files
will be compressed multiple times, so it is likely that -o
would be used in experiments with -N (and possibly -V) to
determine the best compression tool for the local environment
and PCP archives.
-t dir, --dir=dir
When decompressing any compressed files will (by default) be
replaced by their decompressed equivalent. The -t option
changes this behavior to create a duplicate, uncompressed
archive in the dir directory.
If archive is a single file, then only that file is
decompressed into dir, but if archive is an archive basename
then all of the files of archive will be copied, and possibly
decompressed, into dir.
If a file is not compressed, then an attempt will first be
made to create a hard link in dir with ln(1) and if this
fails then a copy is made with cp(1).
dir must exist before pmlogdecompress is run.
-V, --verbose
Increase verbosity.
-Z min, --min-zstd-size=min
xz(1) produces smaller compressed files for small input
files, but at some point the input file becomes large enough
that zstd(1) produces smaller compressed files and zstd is
typically much faster.
When both xz and xstd are in consideration (see the -c option
above), then the -Z option allows the user to tune where the
xz to zstd cut-over happens; input files smaller than min (in
bytes) will be compressed with xz else zstd will be used.
The default value for min is 52428800 (50MiB).
-?, --help
Display usage message and exit.
For most users these tools will not be used directly because
explicit compression and decompression of PCP archives is not
required.
Rather, if archive compression is enabled, then this will be done
indirectly from the PCP archive managements scripts
pmlogger_check(1), pmlogger_daily(1) and pmlogger_rewrite(1).
Decompression is handled transparently during archive replay by
the routines that implement the Performance Metrics Programming
Interface (PMAPI).
PCPIntro(1), bzip2(1), gzip(1), pmlogbasename(1), pmlogger(1),
pmlogger_check(1), pmlogger_daily(1), pmlogger_rewrite(1), xz(1),
zstd(1), PMAPI(3) and LOGARCHIVE(5).
This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at
⟨http://www.pcp.io/⟩. If you have a bug report for this manual
page, send it to pcp@groups.io. This page was obtained from the
project's upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2025-02-02.
(At that time, the date of the most recent commit that was found
in the repository was 2025-01-30.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMLOGCOMPRESS(1)
Pages that refer to this page: pmlogger_daily(1), pmlogger_merge(1)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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