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FUSER(1P)                  POSIX Programmer's Manual                 FUSER(1P)
PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       fuser -- list process IDs of all processes that have one or more  files
       open
SYNOPSIS
       fuser [-cfu] file...
DESCRIPTION
       The  fuser  utility  shall  write to standard output the process IDs of
       processes running on the local system that have one or more named files
       open.   For block special devices, all processes using any file on that
       device are listed.
       The fuser utility shall write to standard error additional  information
       about the named files indicating how the file is being used.
       Any  output  for  processes running on remote systems that have a named
       file open is unspecified.
       A user may need appropriate privileges to invoke the fuser utility.
OPTIONS
       The fuser utility shall conform  to  the  Base  Definitions  volume  of
       POSIX.1-2008, Section 12.2, Utility Syntax Guidelines.
       The following options shall be supported:
       -c        The  file  is  treated as a mount point and the utility shall
                 report on any files open in the file system.
       -f        The report shall be only for the named files.
       -u        The user name, in parentheses, associated with  each  process
                 ID  written  to  standard output shall be written to standard
                 error.
OPERANDS
       The following operand shall be supported:
       file      A pathname on  which  the  file  or  file  system  is  to  be
                 reported.
STDIN
       Not used.
INPUT FILES
       The user database.
ENVIRONMENT VARIABLES
       The  following  environment  variables  shall  affect  the execution of
       fuser:
       LANG      Provide a default value for  the  internationalization  vari-
                 ables  that are unset or null. (See the Base Definitions vol-
                 ume of POSIX.1-2008, Section 8.2, Internationalization  Vari-
                 ables  for  the  precedence of internationalization variables
                 used to determine the values of locale categories.)
       LC_ALL    If set to a non-empty string value, override  the  values  of
                 all the other internationalization variables.
       LC_CTYPE  Determine  the  locale for the interpretation of sequences of
                 bytes of text data as characters (for example, single-byte as
                 opposed to multi-byte characters in arguments).
       LC_MESSAGES
                 Determine the locale that should be used to affect the format
                 and contents  of  diagnostic  messages  written  to  standard
                 error.
       NLSPATH   Determine the location of message catalogs for the processing
                 of LC_MESSAGES.
ASYNCHRONOUS EVENTS
       Default.
STDOUT
       The fuser utility shall write the process ID  for  each  process  using
       each  file given as an operand to standard output in the following for-
       mat:
           "%d", <process_id>
STDERR
       The fuser utility shall write diagnostic messages to standard error.
       The fuser utility also shall write the following to standard error:
        *  The pathname of each named file is written followed immediately  by
           a <colon>.
        *  For  each  process ID written to standard output, the character 'c'
           shall be written to standard error if the process is using the file
           as  its current directory and the character 'r' shall be written to
           standard error if the process is using the file as its root  direc-
           tory.  Implementations  may  write  other  alphabetic characters to
           indicate other uses of files.
        *  When the -u option is specified, characters indicating the  use  of
           the  file shall be followed immediately by the user name, in paren-
           theses, corresponding to the real user ID of the  process.  If  the
           user  name cannot be resolved from the real user ID of the process,
           the real user ID of the process shall be  written  instead  of  the
           user name.
       When  standard output and standard error are directed to the same file,
       the output shall be interleaved so that the  filename  appears  at  the
       start  of each line, followed by the process ID and characters indicat-
       ing the use of the file. Then, if the -u option is specified, the  user
       name or user ID for each process using that file shall be written.
       A  <newline>  shall  be written to standard error after the last output
       described above for each file operand.
OUTPUT FILES
       None.
EXTENDED DESCRIPTION
       None.
EXIT STATUS
       The following exit values shall be returned:
        0    Successful completion.
       >0    An error occurred.
CONSEQUENCES OF ERRORS
       Default.
       The following sections are informative.
APPLICATION USAGE
       None.
EXAMPLES
       The command:
           fuser -fu .
       writes to standard output the process IDs of processes that  are  using
       the current directory and writes to standard error an indication of how
       those processes are using the directory and the user  names  associated
       with the processes that are using the current directory.
           fuser -c <mount point>
       writes  to  standard output the process IDs of processes that are using
       any file in the file system which  is  mounted  on  <mount  point>  and
       writes to standard error an indication of how those processes are using
       the files.
           fuser <mount point>
       writes to standard output the process IDs of processes that  are  using
       the  file  which is named by <mount point> and writes to standard error
       an indication of how those processes are using the file.
           fuser <block device>
       writes to standard output the process IDs of processes that  are  using
       any  file  which is on the device named by <block device> and writes to
       standard error an indication of how those processes are using the file.
           fuser -f <block device>
       writes to standard output the process IDs of processes that  are  using
       the  file <block device> itself and writes to standard error an indica-
       tion of how those processes are using the file.
RATIONALE
       The definition of the fuser utility follows existing practice.
FUTURE DIRECTIONS
       None.
SEE ALSO
       The Base Definitions volume of  POSIX.1-2008,  Chapter  8,  Environment
       Variables, Section 12.2, Utility Syntax Guidelines
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.unix.org/online.html .
       Any typographical or formatting errors that appear  in  this  page  are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors,  see  https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                            FUSER(1P)