list local system locks


List all local system locks

$ lslocks

List locks with defined column headers

$ lslocks --output [PID],[COMMAND],[PATH]

List locks producing a raw output (no columns), and without column headers

$ lslocks --raw --noheadings

List locks by PID input

$ lslocks --pid [PID]

List locks with json output to stdout

$ lslocks --json


lslocks [options]


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 details.


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

-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,--outputlist 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 Output all available columns.

-p,--pidpid 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.


COMMAND The command name of the process holding the lock.

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

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

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 path.

BLOCKER The PID of the process which blocks the lock.


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


Davidlohr Bueso <>


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


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

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