# Bash 的 lsmem 命令

lsmem [OPTION]...

$ lsmem
RANGE                                  SIZE  STATE REMOVABLE  BLOCK
0x0000000000000000-0x000000005fffffff  1.5G online       yes   0-11
0x0000000100000000-0x000000041fffffff 12.5G online       yes 32-131

Memory block size:       128M
Total online memory:      14G
Total offline memory:      0B
$ lsmem --output-all
RANGE                                  SIZE  STATE REMOVABLE  BLOCK NODE  ZONES
0x0000000000000000-0x0000000007ffffff  128M online       yes      0    0   None
0x0000000008000000-0x000000005fffffff  1.4G online       yes   1-11    0  DMA32
0x0000000100000000-0x000000041fffffff 12.5G online       yes 32-131    0 Normal

Memory block size:       128M
Total online memory:      14G
Total offline memory:      0B

LSMEM(1)                         User Commands                        LSMEM(1)

NAME
       lsmem - list the ranges of available memory with their online status

SYNOPSIS
       lsmem [options]

DESCRIPTION
       The lsmem command lists the ranges of available memory with their
       online status. The listed memory blocks correspond to the memory block
       representation in sysfs. The command also shows the memory block size
       and the amount of memory in online and offline state.

       The default output is compatible with original implementation from
       s390-tools, but it’s strongly recommended to avoid using default
       outputs in your scripts. Always explicitly define expected columns by
       using the --output option together with a columns list in environments
       where a stable output is required.

       The lsmem command lists a new memory range always when the current
       memory block distinguish from the previous block by some output column.
       This default behavior is possible to override by the --split option
       (e.g., lsmem --split=ZONES). The special word "none" may be used to
       ignore all differences between memory blocks and to create as large as
       possible continuous ranges. The opposite semantic is --all to list
       individual memory blocks.

       Note that some output columns may provide inaccurate information if a
       split policy forces lsmem to ignore differences in some attributes. For
       example if you merge removable and non-removable memory blocks to the
       one range than all the range will be marked as non-removable on lsmem
       output.

       Not all columns are supported on all systems. If an unsupported column
       is specified, lsmem prints the column but does not provide any data for
       it.

       Use the --help option to see the columns description.

OPTIONS
       -a, --all
           List each individual memory block, instead of combining memory
           blocks with similar attributes.

       -b, --bytes
           Print the sizes in bytes rather than in a human-readable format.

           By default, the unit, sizes are expressed in, is byte, and unit
           prefixes are in power of 2^10 (1024). Abbreviations of symbols are
           exhibited truncated in order to reach a better readability, by
           exhibiting alone the first letter of them; examples: "1 KiB" and "1
           MiB" are respectively exhibited as "1 K" and "1 M", then omitting
           on purpose the mention "iB", which is part of these abbreviations.

       -J, --json
           Use JSON output format.

       -n, --noheadings
           Do not print a header line.

       -o, --output list
           Specify which output columns to print. Use --help to get a list of
           all supported columns. The default list of columns may be extended
           if list is specified in the format +list (e.g., lsmem -o +NODE).

       --output-all
           Output all available columns.

       -P, --pairs
           Produce output in the form of key="value" pairs. All potentially
           unsafe value characters are hex-escaped (\x<code>).

       -r, --raw
           Produce output in raw format. All potentially unsafe characters are
           hex-escaped (\x<code>).

       -S, --split list
           Specify which columns (attributes) use to split memory blocks to
           ranges. The supported columns are STATE, REMOVABLE, NODE and ZONES,
           or "none". The other columns are silently ignored. For more details
           see DESCRIPTION above.

       -s, --sysroot directory
           Gather memory data for a Linux instance other than the instance
           from which the lsmem command is issued. The specified directory is
           the system root of the Linux instance to be inspected.

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

       --summary[=when]
           This option controls summary lines output. The optional argument
           when can be never, always or only. If the when argument is omitted,
           it defaults to "only". The summary output is suppressed for --raw,
           --pairs and --json.

AUTHORS
       lsmem was originally written by Gerald Schaefer for s390-tools in Perl.
       The C version for util-linux was written by Clemens von Mann, Heiko
       Carstens and Karel Zak.

SEE ALSO
       chmem(8)

REPORTING BUGS
       For bug reports, use the issue tracker at
       https://github.com/util-linux/util-linux/issues.

AVAILABILITY
       The lsmem command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.39.3                 2023-10-23                          LSMEM(1)