lslocks(8) — Linux manual page


LSLOCKS(8)                  System Administration                 LSLOCKS(8)

NAME         top

       lslocks - list local system locks

SYNOPSIS         top

       lslocks [options]

DESCRIPTION         top

       lslocks lists information about all the currently held file locks in
       a Linux system.

       Note that lslocks also lists OFD (Open File Description) locks, these
       locks are not associated with any process (PID is -1).  OFD locks are
       associated with the open file description on which they are acquired.
       This lock type is available since Linux 3.15, see fcntl(2) for more

OPTIONS         top

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

       -i, --noinaccessible
              Ignore lock files which are inaccessible for the current user.

       -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., lslocks -o +BLOCKER).

              Output all available columns.

       -p, --pid pid
              Display only the locks held by the process with this pid.

       -r, --raw
              Use the raw output format.

       -u, --notruncate
              Do not truncate text in columns.

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

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

OUTPUT         top

              The command name of the process holding the lock.

       PID    The process ID of the process which holds the lock or -1 for

       TYPE   The type of lock; can be FLOCK (created with flock(2)), POSIX
              (created with fcntl(2) and lockf(3)) or OFDLCK (created with

       SIZE   Size of the locked file.

       MODE   The lock's access permissions (read, write).  If the process
              is blocked and waiting for the lock, then the mode is
              postfixed with an '*' (asterisk).

       M      Whether the lock is mandatory; 0 means no (meaning the lock is
              only advisory), 1 means yes.  (See fcntl(2).)

       START  Relative byte offset of the lock.

       END    Ending offset of the lock.

       PATH   Full path of the lock.  If none is found, or there are no
              permissions to read the path, it will fall back to the
              device's mountpoint and "..." is appended to the path.  The
              path might be truncated; use --notruncate to get the full

              The PID of the process which blocks the lock.

NOTES         top

       The lslocks command is meant to replace the lslk(8) command,
       originally written by Victor A. Abell <> and unmaintained
       since 2001.

AUTHORS         top

       Davidlohr Bueso <>

SEE ALSO         top

       flock(1), fcntl(2), lockf(3)

AVAILABILITY         top

       The lslocks command is part of the util-linux package and is
       available from

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
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       2020-08-13.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-12.)  If you discover any
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       (which is not part of the original manual page), send a mail to

util-linux                      December 2014                     LSLOCKS(8)

Pages that refer to this page: fcntl(2)fcntl64(2)flock(2)proc(5)procfs(5)