# inotifywait

## NAME



           inotifywait, fsnotifywait - wait for changes to files using
           inotify or fanotify
    


## SYNOPSIS



           **inotifywait**[**-hcmrPqIFS**] [**-e** <event> ] [**-t** <seconds> ] [**--format**
           <fmt> ] [**--timefmt** <fmt> ] <file> [ ... ]
    
           **fsnotifywait**[**-hcmrPqIFS**] [**-e** <event> ] [**-t** <seconds> ] [**--format**
           <fmt> ] [**--timefmt** <fmt> ] <file> [ ... ]
    


## DESCRIPTION



           **inotifywait** efficiently waits for changes to files using Linux's
           inotify(7) interface by default.  It is suitable for waiting for
           changes to files from shell scripts.  It can either exit once an
           event occurs, or continually execute and output events as they
           occur.
    
           **fsnotifywait** is similar to **inotifywait** but it is using Linux's
           fanotify(7) interface by default. If explicitly specified, it uses
           the inotify(7) interface.
    


## OUTPUT



           **inotifywait** and **fsnotifywait** will output diagnostic information on
           standard error and event information on standard output.  The
           event output can be configured, but by default it consists of
           lines of the following form:
    
           **watched_filename EVENT_NAMES event_filename**
    
           **watched_filename**
                  is the name of the file on which the event occurred.  If
                  the file is a directory, a trailing slash is output.
    
           **EVENT_NAMES**
                  are the names of the inotify events which occurred,
                  separated by commas.
    
           **event_filename**
                  is output only when the event occurred on a directory, and
                  in this case the name of the file within the directory
                  which caused this event is output.
    
                  By default, any special characters in filenames are not
                  escaped in any way.  This can make the output of
                  inotifywait difficult to parse in awk scripts or similar.
                  The **--csv** and **--format** options will be helpful in this
                  case.
    


## OPTIONS



           **-h, --help**
                  Output some helpful usage information.
    
           **@ <file>**
                  When watching a directory tree recursively, exclude the
                  specified file from being watched.  The file must be
                  specified with a relative or absolute path according to
                  whether a relative or absolute path is given for watched
                  directories.  If a specific path is explicitly both
                  included and excluded, it will always be watched.
    
                  **Note:** If you need to watch a directory or file whose name
                  starts with @, give the absolute path.
    
           **--fromfile <file>**
                  Read filenames to watch or exclude from a file, one
                  filename per line.  If filenames begin with @ they are
                  excluded as described above.  If <file> is `-', filenames
                  are read from standard input.  Use this option if you need
                  to watch too many files to pass in as command line
                  arguments.
    
           **-m, --monitor**
                  Instead of exiting after receiving a single event, execute
                  indefinitely.  The default behaviour is to exit after the
                  first event occurs.
    
           **-d, --daemon**
                  Same as --monitor, except run in the background logging
                  events to a file that must be specified by --outfile.
                  Implies --syslog.
    
           **-o, --outfile <file>**
                  Output events to <file> rather than stdout.
    
           **-s, --syslog**
                  Output errors to syslog(3) system log module rather than
                  stderr.
    
           **-P, --no-dereference**
                  Do not follow symlinks.
    
           **-r, --recursive**
                  Watch all subdirectories of any directories passed as
                  arguments.  Watches will be set up recursively to an
                  unlimited depth.  Symbolic links are not traversed.  Newly
                  created subdirectories will also be watched.
    
                  **Warning:** If you use this option while watching the root
                  directory of a large tree, it may take quite a while until
                  all inotify watches are established, and events will not be
                  received in this time.  Also, since one inotify watch will
                  be established per subdirectory, it is possible that the
                  maximum amount of inotify watches per user will be reached.
                  The default maximum is 8192; it can be increased by writing
                  to **/proc/sys/fs/inotify/max_user_watches**.
    
           **-q, --quiet**
                  If specified once, the program will be less verbose.
                  Specifically, it will not state when it has completed
                  establishing all inotify watches.
    
                  If specified twice, the program will output nothing at all,
                  except in the case of fatal errors.
    
           **--exclude <pattern>**
                  Do not process any events for the subset of files whose
                  filenames match the specified POSIX regular expression,
                  case sensitive.
    
           **--excludei <pattern>**
                  Do not process any events for the subset of files whose
                  filenames match the specified POSIX regular expression,
                  case insensitive.
    
           **--include <pattern>**
                  Process events only for the subset of files whose filenames
                  match the specified POSIX regular expression, case
                  sensitive.  When used with --recursive, events will still
                  be generated for matching files inside newly created
                  directories, even if the directory names themselves do not
                  match the pattern.
    
           **--includei <pattern>**
                  Process events only for the subset of files whose filenames
                  match the specified POSIX regular expression, case
                  insensitive.
    
           **-t <seconds>, --timeout <seconds>**
                  Exit if an appropriate event has not occurred within
                  <seconds> seconds. If <seconds> is zero (the default), wait
                  indefinitely for an event.
    
           **-e <event>, --event <event>**
                  Listen for specific event(s) only.  The events which can be
                  listened for are listed in the **EVENTS** section.  This option
                  can be specified more than once.  If omitted, all events
                  are listened for.
    
           **-c, --csv**
                  Output in CSV (comma-separated values) format.  This is
                  useful when filenames may contain spaces, since in this
                  case it is not safe to simply split the output at each
                  space character.
    
           **--timefmt <fmt>**
                  Set a time format string as accepted by strftime(3) for use
                  with the `%T' conversion in the --format option.
    
           **--no-newline**
                  Don't print newline symbol after user-specified format in
                  the --format option.
    
           **--format <fmt>**
                  Output in a user-specified format, using printf-like
                  syntax.  The event strings output are limited to around
                  4000 characters and will be truncated to this length.  The
                  following conversions are supported:
    
           %w     This will be replaced with the name of the Watched file on
                  which an event occurred.  When an event occurs within a
                  Watched directory or when watching with fanotify, this will
                  be replaced with the name of the Directory in which the
                  event occurred.
    
           %f     When an event occurs within a Watched directory or when
                  watching with fanotify, this will be replaced with the name
                  of the File which caused the event to occur.  Otherwise,
                  this will be replaced with an empty string.
    
           %e     Replaced with the Event(s) which occurred, comma-separated.
    
           %Xe    Replaced with the Event(s) which occurred, separated by
                  whichever character is in the place of `X'.
    
           %T     Replaced with the current Time in the format specified by
                  the --timefmt option, which should be a format string
                  suitable for passing to strftime(3).
    
           %0     Replaced with NUL.
    
           %n     Replaced with Line Feed.
    
           **-I, --inotify**
                  Watch using inotify (default for **inotifywait**).
    
           **-F, --fanotify**
                  Watch using fanotify (default for **fsnotifywait**).  fanotify
                  support for reporting events with inotify compatible
                  information was added in kernel v5.9.  With older kernels
                  the command will fail.  As of kernel v5.12, fanotify
                  requires admin privileges.
    
           **-S, --filesystem**
                  Watch entire filesystem of any directories passed as
                  arguments using fanotify.
    


## EXIT STATUS



           **0** The program executed successfully, and an event occurred
                  which was being listened for.
    
           **1** An error occurred in execution of the program, or an event
                  occurred which was not being listened for.  The latter
                  generally occurs if something happens which forcibly
                  removes the inotify watch, such as a watched file being
                  deleted or the filesystem containing a watched file being
                  unmounted.
    
           **2** The **-t** option was used and an event did not occur in the
                  specified interval of time.
    


## EVENTS



           The following events are valid for use with the **-e** option:
    
           **access** A watched file or a file within a watched directory was
                  read from.
    
           **modify** A watched file or a file within a watched directory was
                  written to.
    
           **attrib** The metadata of a watched file or a file within a watched
                  directory was modified.  This includes timestamps, file
                  permissions, extended attributes etc.
    
           **close_write**
                  A watched file or a file within a watched directory was
                  closed, after being opened in writable mode.  This does not
                  necessarily imply the file was written to.
    
           **close_nowrite**
                  A watched file or a file within a watched directory was
                  closed, after being opened in read-only mode.
    
           **close** A watched file or a file within a watched directory was
                  closed, regardless of how it was opened.  Note that this is
                  actually implemented simply by listening for both
                  **close_write** and **close_nowrite,** hence all close events
                  received will be output as one of these, not **CLOSE.**
    
           **open** A watched file or a file within a watched directory was
                  opened.
    
           **moved_to**
                  A file or directory was moved into a watched directory.
                  This event occurs even if the file is simply moved from and
                  to the same directory.
    
           **moved_from**
                  A file or directory was moved from a watched directory.
                  This event occurs even if the file is simply moved from and
                  to the same directory.
    
           **move** A file or directory was moved from or to a watched
                  directory.  Note that this is actually implemented simply
                  by listening for both **moved_to** and **moved_from,** hence all
                  move events received will be output as one or both of
                  these, not **MOVE.**
    
           **move_self**
                  A watched file or directory was moved. After this event,
                  the file or directory is no longer being watched.
    
           **create** A file or directory was created within a watched directory.
    
           **delete** A file or directory within a watched directory was deleted.
    
           **delete_self**
                  A watched file or directory was deleted.  After this event
                  the file or directory is no longer being watched.  Note
                  that this event can occur even if it is not explicitly
                  being listened for.
    
           **unmount**
                  The filesystem on which a watched file or directory resides
                  was unmounted.  After this event the file or directory is
                  no longer being watched.  Note that this event can occur
                  even if it is not explicitly being listened to.
    


## EXAMPLES



       **Example 1**
           Running inotifywait at the command-line to wait for any file in
           the `test' directory to be accessed.  After running inotifywait,
           `cat test/foo' is run in a separate console.
    
           % inotifywait test
           Setting up watches.
           Watches established.
           test/ ACCESS foo
    
       **Example 2**
           A short shell script to efficiently wait for httpd-related log
           messages and do something appropriate.
    
           #!/bin/sh
           while ! inotifywait -e modify /var/log/messages; do
             if tail -n1 /var/log/messages | grep httpd; then
               kdialog --msgbox "Apache needs love!"
             fi
           done
    
       **Example 3**
           A custom output format is used to watch `~/test'.  Meanwhile,
           someone runs `touch ~/test/badfile; touch ~/test/goodfile; rm
           ~/test/badfile' in another console.
    
           % inotifywait -m -r --format '%:e %f' ~/test
           Setting up watches.  Beware: since -r was given, this may take a while!
           Watches established.
           CREATE badfile
           OPEN badfile
           ATTRIB badfile
           CLOSE_WRITE:CLOSE badfile
           CREATE goodfile
           OPEN goodfile
           ATTRIB goodfile
           CLOSE_WRITE:CLOSE goodfile
           DELETE badfile
    
       **Example 4**
           Enforce file permissions in directory `~/test'
    
           inotifywait -qmr -e 'moved_to,create' --format '%w%f%0' --no-newline ~/test |\
               while IFS= read -r -d '' file
               do
                  chmod -v a+rX "$file"
               done
    


## CAVEATS



           When using inotifywait, the filename that is outputted is not
           guaranteed to be up to date after a move because it is the inode
           that is being monitored. Additionally, none of the observed
           operations are guaranteed to have been performed on the filename
           inotifywait was instructed to monitor in cases when the file is
           known by several names in the filesystem.
    


## BUGS



           There are race conditions in the recursive directory watching code
           which can cause events to be missed if they occur in a directory
           immediately after that directory is created.  This is probably not
           fixable.
    
           It is assumed the inotify event queue will never overflow.
    


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