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Manual Pages  — FUSER


fuser – list IDs of all processes that have one or more files open



fuser [-cfkmu] [-M core] [-N system] [-s signal] file ...


The fuser utility writes to stdout the PIDs of processes that have one or more named files open. For block and character special devices, all processes using files on that device are listed. A file is considered open by a process if it was explicitly opened, is the working directory, root directory, jail root directory, active executable text, kernel trace file or the controlling terminal of the process. If -m option is specified, the fuser utility will also look through mmapped files.

The following options are available:
  Treat files as mount point and report on any files open in the file system.
  The report must be only for named files.
  Send signal to reported processes (SIGKILL by default).
  Search through mmapped files too.
  Write the user name associated with each process to stderr.
  Extract values associated with the name list from the specified core instead of the default /dev/kmem.
  Extract the name list from the specified system instead of the default, which is the kernel image the system has booted from.
  Use given signal name instead of default SIGKILL.

The following symbols, written to stderr will indicate how files is used:
r The file is the root directory of the process.
c The file is the current workdir directory of the process.
j The file is the jail-root of the process.
t The file is the kernel tracing file for the process.
x The file is executable text of the process.
y The process use this file as its controlling tty.
m The file is mmapped.
w The file is open for writing.
a The file is open as append only (O_APPEND was specified).
d The process bypasses fs cache while writing to this file (O_DIRECT was specified).
s Shared lock is hold.
e Exclusive lock is hold.


The fuser utility returns 0 on successful completion and >0 otherwise.


The command: "fuser -fu ." writes to standard output the process IDs of processes that are using the current directory and writes to stderr an indication of how those processes are using the directory and user names associated with the processes that are using this directory.


fstat(1), ps(1), systat(1), iostat(8), pstat(8), vmstat(8)


The fuser utility is expected to conform to IEEE Std 1003.1-2004 ("POSIX.1").


The fuser utility appeared in FreeBSD 9.0 .


The fuser utility and this manual page was written by Stanislav Sedov <Mt stas@FreeBSD.org>.


Since fuser takes a snapshot of the system, it is only correct for a very short period of time. When working via kvm(3) interface the report will be limited to filesystems the fuser utility knows about (currently only cd9660, devfs, nfs, ntfs, nwfs, udf, ufs and zfs).

FUSER (1) May 13, 2011

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