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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | PCP ENVIRONMENT | SEE ALSO | COLOPHON |
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PCP-FREE(1) General Commands Manual PCP-FREE(1)
pcp-free - report on free and used memory in the system
pcp [pcp options] free [-bkmgroltVw?] [-c count] [-s interval]
pcp-free gives a summary display of the total amount of free and
used physical memory and swap in the system, as well as the caches
used by the kernel.
When invoked via the pcp(1) command, the -h/--host, -a/--archive,
-O/--origin, -s/--samples, -t/--interval, -Z/--timezone and
several other pcp options become indirectly available, see
PCPIntro(1) for their descriptions.
The displayed columns are:
total Total installed memory (MemTotal and SwapTotal in
/proc/meminfo)
used Used memory (calculated as total - free - buffers - cache)
free Unused memory (MemFree and SwapFree in /proc/meminfo)
shared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)
buffers
Memory used by kernel buffers (Buffers in /proc/meminfo)
cache Memory used by the page cache and slabs (Cached and
SReclaimable in /proc/meminfo)
buff/cache
Sum of buffers and cache
available
Estimation of how much memory is available for starting new
applications, without swapping. Unlike the data provided
by the cache or free fields, this field takes into account
page cache and also that not all reclaimable memory slabs
will be reclaimed due to items being in use (MemAvailable
in /proc/meminfo).
The available command line options are:
-b, --bytes
Display the amount of memory in bytes.
-c count, --samples=count, --count=count
Terminate the display after count iterations. See also -s.
-g, --gigabytes
Display the amount of memory in gigabytes.
-k, --kilobytes
Display the amount of memory in kilobytes. This is the
default.
-l, --lohi
Display detailed low and high memory statistics.
-m, --megabytes
Display the amount of memory in megabytes.
-o Disable the display of a "buffer adjusted" line. If the -o
option is not specified, free subtracts buffer memory from
the used memory and adds it to the free memory reported.
-r, --terabytes
Display the amount of memory in terabytes.
-s delay, --interval=delay, --seconds=delay
Activate continuous polling delay seconds apart. You may
specify any floating point number for delay, or indeed any
valid pmParseInterval(3) specification, which includes
microsecond resolution delay times. This can be used in
conjunction with the -c option.
-t, --total
Display a line containing the totals.
-V, --version
Display version number and exit.
-w, --wide
Switch to the wide mode. The wide mode produces lines longer
than 80 characters. In this mode buffers and cache are
reported in two separate columns.
-?, --help
Display usage message and exit.
pcp-free is inspired by the free(1) command and aims to be command
line and output compatible with it.
Environment variables with the prefix PCP_ are used to
parameterize the file and directory names used by PCP. On each
installation, the file /etc/pcp.conf contains the local values for
these variables. The $PCP_CONF variable may be used to specify an
alternative configuration file, as described in pcp.conf(5).
For environment variables affecting PCP tools, see
pmGetOptions(3).
PCPIntro(1), pcp(1), free(1), pmParseInterval(3) and environ(7).
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 2025-08-11.
(At that time, the date of the most recent commit that was found
in the repository was 2025-08-11.) 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 PCP-FREE(1)
Pages that refer to this page: pcp(1)
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HTML rendering created 2025-09-06 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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