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/>.