lslocks — list local system locks
Examples (TL;DR)
-
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
Synopsis
lslocks [options]
Description
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.
Options
- -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, --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.
- -V, --version
Display version information and exit.
- -h, --help
Display help text and exit.
Output
- 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.
Notes
The lslocks command is meant to replace the lslk(8) command, originally written by Victor A. Abell <abe@purdue.edu> and unmaintained since 2001.
See Also
Availability
The lslocks command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.