Manual: lslocks

LSLOCKS(8)					    System Administration					  LSLOCKS(8)

NAME
       lslocks - list local system locks

SYNOPSIS
       lslocks [options]

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

OPTIONS
       -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.

       -H, --list-columns
	   List the available columns, use with --json or --raw to get output in machine-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, --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
	   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.

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

       -V, --version
	   Display version and exit.

OUTPUT
       COMMAND
	   The command name of the process holding the lock.

       PID
	   The process ID of the process.

       TYPE
	   The type of lock; can be LEASE (created with fcntl(2)), 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.

       INODE
	   The inode number.

       MAJ:MIN
	   The major:minor device number.

       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.

       HOLDERS
	   The holder(s) of the lock. The format of the holder is PID,COMMAND,FD. If a lock is an open file
	   description-oriented lock, there can be more than one holder for the lock. See the NOTES below.

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

       "The process holding the lock" for leases, FLOCK locks, and OFD locks is a fake-concept. They are associated with the
       open file description on which they are acquired. With fork(2) and/or cmsg(3), multiple processes can share an open
       file description. So the holder process of a lease (or a lock) is not uniquely determined. lslocks shows the one of
       the holder processes in COMMAND and PID columns.

AUTHORS
       Davidlohr Bueso 

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

REPORTING BUGS
       For bug reports, use the issue tracker .

AVAILABILITY
       The lslocks command is part of the util-linux package which can be downloaded from Linux Kernel Archive
       .

util-linux 2.41.3					 2025-12-15						  LSLOCKS(8)