131 lines
3.4 KiB
Groff
131 lines
3.4 KiB
Groff
.\" -*-Nroff-*-
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.\" This page Copyright (C) 1993 Matt Welsh, mdw@sunsite.unc.edu.
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.\" Long options where added at April 15th, 2011.
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.\" Freely distributable under the terms of the GPL
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.TH FREE 1 "July 2014" "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 installed memory (MemTotal and SwapTotal in /proc/meminfo)
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.TP
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\fBused\fR
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Used memory (calculated as \fBtotal\fR - \fBfree\fR - \fBbuffers\fR - \fBcache\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, available on
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kernels 2.6.32, displayed as zero if not available)
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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 Slab 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\-\-kilo\fR
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Display the amount of memory in kilobytes. This is the default.
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.TP
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\fB\-m\fR, \fB\-\-mega\fR
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Display the amount of memory in megabytes.
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.TP
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\fB\-g\fR, \fB\-\-giga\fR
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Display the amount of memory in gigabytes.
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.TP
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\fB\-\-tera\fR
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Display the amount of memory in terabytes.
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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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K = kilos
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M = megas
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G = gigas
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T = teras
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.fi
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.sp
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If unit is missing, and you have petabyte of RAM or swap, the number is in
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terabytes 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\-s\fR, \fB\-\-seconds\fR \fIseconds\fR
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Continuously display the result delay
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.I seconds
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apart. You may actually specify any floating point number for
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.IR delay ,
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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 power of 1000 not 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\-\-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 "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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.SH AUTHORS
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Written by Brian Edmonds.
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.SH "REPORTING BUGS"
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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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