lsmem(1) — Linux manual page


LSMEM(1)                      User Commands                     LSMEM(1)

NAME         top

       lsmem - list the ranges of available memory with their online

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 format.

       -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 value characters are hex-escaped

       -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

       -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
       2021-03-21.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-19.)  If you
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       manual page), send a mail to

util-linux                    October 2016                      LSMEM(1)

Pages that refer to this page: chmem(8)