b31ac2dcce
Added the -L --line option to free to show a small set of memory statistics on a single line of 80 characters. Largely based on the work of @Ulenrich1 and updated to the new API. References: procps-ng/procps#156 Signed-off-by: Craig Small <csmall@dropbear.xyz>
170 lines
4.8 KiB
Groff
170 lines
4.8 KiB
Groff
.\"
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.\" Copyright (c) 2011-2023 Craig Small <csmall@dropbear.xyz>
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.\" Copyright (c) 2013-2023 Jim Warner <james.warner@comcast.net>
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.\" Copyright (c) 2011-2012 Sami Kerola <kerolasa@iki.fi>
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.\" Copyright (c) 2002-2003 Albert Cahalan
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.\" Copyright (c) 1993 Matt Welsh <mdw@sunsite.unc.edu>
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.\"
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.\" This program is free software; you can redistribute it and/or modify
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.\" it under the terms of the GNU General Public License as published by
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.\" the Free Software Foundation; either version 2 of the License, or
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.\" (at your option) any later version.
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.\"
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.\"
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.TH FREE 1 "2023-05-02" "procps-ng" "User Commands"
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.SH NAME
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free \- Display amount of free and used memory in the system
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.SH SYNOPSIS
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.B free
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.RI [ options ]
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.SH DESCRIPTION
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.B free
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displays the total amount of free and used physical and swap memory in the
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system, as well as the buffers and caches used by the kernel. The
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information is gathered by parsing /proc/meminfo. The displayed
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columns are:
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.TP
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\fBtotal\fR
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Total usable memory (MemTotal and SwapTotal in /proc/meminfo). This includes
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the physical and swap memory minus a few reserved bits and kernel binary code.
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.TP
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\fBused\fR
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Used or unavailable memory (calculated as \fBtotal\fR - \fBavailable\fR)
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.TP
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\fBfree\fR
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Unused memory (MemFree and SwapFree in /proc/meminfo)
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.TP
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\fBshared\fR
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Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)
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.TP
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\fBbuffers\fR
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Memory used by kernel buffers (Buffers in /proc/meminfo)
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.TP
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\fBcache\fR
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Memory used by the page cache and slabs (Cached and SReclaimable in /proc/meminfo)
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.TP
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\fBbuff/cache\fR
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Sum of \fBbuffers\fR and \fBcache\fR
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.TP
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\fBavailable\fR
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Estimation of how much memory is available for starting
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new applications, without swapping. Unlike the data
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provided by the \fBcache\fR or \fBfree\fR fields,
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this field takes into account page cache and also that
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not all reclaimable memory slabs will be reclaimed
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due to items being in use (MemAvailable in /proc/meminfo, available on
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kernels 3.14, emulated on kernels 2.6.27+, otherwise the same as \fBfree\fR)
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.SH OPTIONS
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.TP
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\fB\-b\fR, \fB\-\-bytes\fR
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Display the amount of memory in bytes.
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.TP
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\fB\-k\fR, \fB\-\-kibi\fR
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Display the amount of memory in kibibytes. This is the default.
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.TP
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\fB\-m\fR, \fB\-\-mebi\fR
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Display the amount of memory in mebibytes.
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.TP
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\fB\-g\fR, \fB\-\-gibi\fR
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Display the amount of memory in gibibytes.
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.TP
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\fB\-\-tebi\fR
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Display the amount of memory in tebibytes.
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.TP
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\fB\-\-pebi\fR
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Display the amount of memory in pebibytes.
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.TP
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\fB\-\-kilo\fR
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Display the amount of memory in kilobytes. Implies --si.
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.TP
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\fB\-\-mega\fR
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Display the amount of memory in megabytes. Implies --si.
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.TP
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\fB\-\-giga\fR
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Display the amount of memory in gigabytes. Implies --si.
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.TP
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\fB\-\-tera\fR
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Display the amount of memory in terabytes. Implies --si.
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.TP
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\fB\-\-peta\fR
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Display the amount of memory in petabytes. Implies --si.
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.TP
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\fB\-h\fR, \fB\-\-human\fP
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Show all output fields automatically scaled to shortest three digit unit and
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display the units of print out. Following units are used.
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.sp
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.nf
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B = bytes
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Ki = kibibyte
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Mi = mebibyte
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Gi = gibibyte
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Ti = tebibyte
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Pi = pebibyte
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.fi
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.sp
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If unit is missing, and you have exbibyte of RAM or swap, the number is in
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tebibytes and columns might not be aligned with header.
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.TP
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\fB\-w\fR, \fB\-\-wide\fR
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Switch to the wide mode. The wide mode produces lines longer
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than 80 characters. In this mode \fBbuffers\fR and \fBcache\fR
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are reported in two separate columns.
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.TP
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\fB\-c\fR, \fB\-\-count\fR \fIcount\fR
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Display the result
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.I count
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times. Requires the
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.B \-s
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option.
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.TP
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\fB\-l\fR, \fB\-\-lohi\fR
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Show detailed low and high memory statistics.
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.TP
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\fB\-L\fR, \fB\-\-line\fR
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Show output on a single line, often used with the
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.B \-s
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option to show memory statistics repeatedly.
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.TP
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\fB\-s\fR, \fB\-\-seconds\fR \fIdelay\fR
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Continuously display the result \fIdelay\fR seconds
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apart. You may actually specify any floating point number for
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\fIdelay\fR using either . or , for decimal point.
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.BR usleep (3)
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is used for microsecond resolution delay times.
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.TP
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\fB\-\-si\fR
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Use kilo, mega, giga etc (power of 1000) instead of kibi, mebi, gibi (power
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of 1024).
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.TP
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\fB\-t\fR, \fB\-\-total\fR
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Display a line showing the column totals.
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.TP
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\fB\-v\fR, \fB\-\-committed\fR
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Display a line showing the memory commit limit and amount of committed/uncommitted
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memory. The \fBtotal\fR column on this line will display the memory commit
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limit. This line is relevant if memory overcommit is disabled.
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.TP
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\fB\-\-help\fR
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Print help.
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.TP
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\fB\-V\fR, \fB\-\-version\fR
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Display version information.
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.PD
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.SH FILES
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.TP
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/proc/meminfo
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memory information
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.PD
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.SH BUGS
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The value for the \fBshared\fR column is not available from kernels before
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2.6.32 and is displayed as zero.
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.TP
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Please send bug reports to
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.UR procps@freelists.org
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.UE
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.SH "SEE ALSO"
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.BR ps (1),
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.BR slabtop (1),
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.BR top "(1),
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.BR vmstat (8).
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