PROLOGThis 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.
NAMEfuser --- list process IDs of all processes that have one or more files open
fuser [-cfu] file...
DESCRIPTIONThe 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.
OPTIONSThe 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:
- The file is treated as a mount point and the utility shall report on any files open in the file system.
- The report shall be only for the named files.
- The user name, in parentheses, associated with each process ID written to standard output shall be written to standard error.
OPERANDSThe following operand shall be supported:
- A pathname on which the file or file system is to be reported.
INPUT FILESThe user database.
ENVIRONMENT VARIABLESThe following environment variables shall affect the execution of fuser:
- Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.1-2008, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.)
- If set to a non-empty string value, override the values of all the other internationalization variables.
- 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).
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
- Determine the location of message catalogs for the processing of LC_MESSAGES.
STDOUTThe fuser utility shall write the process ID for each process using each file given as an operand to standard output in the following format:
STDERRThe 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 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 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.
EXIT STATUSThe following exit values shall be returned:
- Successful completion.
- An error occurred.
CONSEQUENCES OF ERRORSDefault.
The following sections are informative.
fuser -fu .
fuser -c <mount point>
fuser <mount point>
fuser <block device>
fuser -f <block device>
RATIONALEThe definition of the fuser utility follows existing practice.
SEE ALSOThe Base Definitions volume of POSIX.1-2008, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines
COPYRIGHTPortions 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 www.unix.org/online.html .
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