LSMEM(1)                        User Commands                       LSMEM(1)

NAME         top

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

SYNOPSIS         top

       lsmem [options]

DESCRIPTION         top

       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 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         top

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

       -b, --bytes
              Print the SIZE column in bytes rather than in a human-readable

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

       -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 available columns.

       -P, --pairs
              Produce output in the form of key="value" pairs.  All
              potentially unsafe 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 another 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.

       -V, --version
              Display version information and exit.

              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         top

       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         top


AVAILABILITY         top

       The lsmem command is part of the util-linux package and is available
       from Linux Kernel Archive 

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2020-05-27.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-05-27.)  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

util-linux                      October 2016                        LSMEM(1)

Pages that refer to this page: chmem(8)