Ubuntu Manpage: fuser - list process IDs of all processes that have one or more files open

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 privilege to invoke the fuser utility.

OPTIONS

       The fuser utility shall conform to the Base Definitions volume  of  IEEE Std 1003.1-2001,  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 variables that are unset or null. (See the
              Base Definitions volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization  Variables  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 format:

              "%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 directory. 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 parentheses, corresponding to the process' real user ID. If the user
name cannot be resolved from the process' real user ID, the process' real user ID 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 indicating
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.

RATIONALE

       The definition of the fuser utility follows existing practice.

FUTURE DIRECTIONS

       None.

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc  and  The  Open Group. 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.opengroup.org/unix/online.html .