дождитесь изменений в файлах с помощью inotify или fanotify (wait for changes to files using inotify or fanotify)
Имя (Name)
inotifywait, fsnotifywait - wait for changes to files using
inotify or fanotify
Синопсис (Synopsis)
inotifywait [-hcmrPq] [-e <event> ] [-t <seconds> ] [--format
<fmt> ] [--timefmt <fmt> ] <file> [ ... ]
fsnotifywait [-hcmrPqIFS] [-e <event> ] [-t <seconds> ] [--format
<fmt> ] [--timefmt <fmt> ] <file> [ ... ]
Описание (Description)
inotifywait efficiently waits for changes to files using Linux's
inotify(7) interface. 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 sepcified, it
uses the inotify(7) interface.
Вывод (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.
Параметры (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.
--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.
%f When an event occurs within a directory, 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.
fsnotifywait
The following additional options are available:
-I, --inotify
Watch using inotify.
-F, --fanotify
Watch using fanotify (default). 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.
Статус выхода (Exit)
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.
События (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 writeable 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.
Примеры (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
Предостережение (Caveat)
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.
Ошибки (баги) (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.
