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.TH FUSER "1P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"

.SH 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.

.SH NAME

fuser

\(em list process IDs of all processes that have one or more files open

.SH SYNOPSIS

.LP

.nf

fuser \fB[\fR\(micfu\fB] \fIfile\fR...

.fi

.SH DESCRIPTION

The

.IR 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.

.P

The

.IR fuser

utility shall write to standard error additional information about the

named files indicating how the file is being used.

.P

Any output for processes running on remote systems that have a named

file open is unspecified.

.P

A user may need appropriate privileges to invoke the

.IR fuser

utility.

.SH OPTIONS

The

.IR fuser

utility shall conform to the Base Definitions volume of POSIX.1\(hy2008,

.IR "Section 12.2" ", " "Utility Syntax Guidelines".

.P

The following options shall be supported:

.IP "\fB\(mic\fR" 10

The file is treated as a mount point and the utility shall report

on any files open in the file system.

.IP "\fB\(mif\fR" 10

The report shall be only for the named files.

.IP "\fB\(miu\fR" 10

The user name, in parentheses, associated with each process ID written

to standard output shall be written to standard error.

.SH OPERANDS

The following operand shall be supported:

.IP "\fIfile\fP" 10

A pathname on which the file or file system is to be reported.

.SH STDIN

Not used.

.SH "INPUT FILES"

The user database.

.SH "ENVIRONMENT VARIABLES"

The following environment variables shall affect the execution of

.IR fuser :

.IP "\fILANG\fP" 10

Provide a default value for the internationalization variables that are

unset or null. (See the Base Definitions volume of POSIX.1\(hy2008,

.IR "Section 8.2" ", " "Internationalization Variables"

for the precedence of internationalization variables used to determine

the values of locale categories.)

.IP "\fILC_ALL\fP" 10

If set to a non-empty string value, override the values of all the

other internationalization variables.

.IP "\fILC_CTYPE\fP" 10

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).

.IP "\fILC_MESSAGES\fP" 10

.br

Determine the locale that should be used to affect the format and

contents of diagnostic messages written to standard error.

.IP "\fINLSPATH\fP" 10

Determine the location of message catalogs for the processing of

.IR LC_MESSAGES .

.SH "ASYNCHRONOUS EVENTS"

Default.

.SH STDOUT

The

.IR fuser

utility shall write the process ID for each process using each file

given as an operand to standard output in the following format:

.sp

.RS 4

.nf

\fB

"%d", <\fIprocess_id\fR>

.fi \fR

.P

.RE

.SH STDERR

The

.IR fuser

utility shall write diagnostic messages to standard error.

.P

The

.IR fuser

utility also shall write the following to standard error:

.IP " *" 4

The pathname of each named file is written followed immediately by a

<colon>.

.IP " *" 4

For each process ID written to standard output, the character

.BR 'c' 

shall be written to standard error if the process is using the file as

its current directory and the character

.BR '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.

.IP " *" 4

When the

.BR \(miu

option is specified, characters indicating the use of the file shall be

followed immediately by the user name, in parentheses, 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.

.P

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

.BR \(miu

option is specified, the user name or user ID for each process using

that file shall be written.

.P

A

<newline>

shall be written to standard error after the last output

described above for each

.IR file

operand.

.SH "OUTPUT FILES"

None.

.SH "EXTENDED DESCRIPTION"

None.

.SH "EXIT STATUS"

The following exit values shall be returned:

.IP "\00" 6

Successful completion.

.IP >0 6

An error occurred.

.SH "CONSEQUENCES OF ERRORS"

Default.

.LP

.IR "The following sections are informative."

.SH "APPLICATION USAGE"

None.

.SH EXAMPLES

The command:

.sp

.RS 4

.nf

\fB

fuser \(mifu .

.fi \fR

.P

.RE

.P

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.

.sp

.RS 4

.nf

\fB

fuser \(mic <\fImount point\fR>

.fi \fR

.P

.RE

.P

writes to standard output the process IDs of processes that are using

any file in the file system which is mounted on <\fImount point\fR>

and writes to standard error an indication of how those processes are

using the files.

.sp

.RS 4

.nf

\fB

fuser <\fImount point\fR>

.fi \fR

.P

.RE

.P

writes to standard output the process IDs of processes that are using

the file which is named by <\fImount point\fR> and writes to standard

error an indication of how those processes are using the file.

.sp

.RS 4

.nf

\fB

fuser <\fIblock device\fR>

.fi \fR

.P

.RE

.P

writes to standard output the process IDs of processes that are using

any file which is on the device named by <\fIblock device\fR> and

writes to standard error an indication of how those processes are using

the file.

.sp

.RS 4

.nf

\fB

fuser \(mif <\fIblock device\fR>

.fi \fR

.P

.RE

.P

writes to standard output the process IDs of processes that are using

the file <\fIblock device\fR> itself and writes to standard error an

indication of how those processes are using the file.

.SH RATIONALE

The definition of the

.IR fuser

utility follows existing practice.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

The Base Definitions volume of POSIX.1\(hy2008,

.IR "Chapter 8" ", " "Environment Variables",

.IR "Section 12.2" ", " "Utility Syntax Guidelines"

.SH 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

Electrical 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.kernel.org/doc/man-pages/reporting_bugs.html .