inotifywait：在被监控的文件或目录上等待特定文件系统事件（open、close、delete等）发生，执行后处于阻塞转态，适合在shell脚本中使用。
[root@server inotify-tools]# ./bin/inotifywait --help
inotifywait 3.14
Wait for a particular event on a file or set of files.
Usage: inotifywait [ options ] file1 [ file2 ] [ file3 ] [ ... ]
Options:
-h|--help Show this help text.
@<file> Exclude the specified file from being watched.
--exclude <pattern>
Exclude all events on files matching the
extended regular expression <pattern>.
--excludei <pattern>
Like --exclude but case insensitive. #排除文件或目录时，不区分大小写
-m|--monitor Keep listening for events forever. Without
this option, inotifywait will exit after one
event
is received. #始终保持事件监听状态
-d|--daemon Same as --monitor, except run in the background
logging events to a file specified by --outfile.
Implies --syslog.
-r|--recursive Watch directories recursively. #递归查询目录
--fromfile <file>
Read files to watch from <file> or `-‘ for stdin.
-o|--outfile <file>
Print events to <file> rather than stdout.
-s|--syslog Send errors to syslog rather than stderr.
-q|--quiet Print less (only print events). #打印很少的信息，仅仅打印监控事件的信息
-qq Print nothing (not even events).
--format <fmt> Print using a specified printf-like format
string; read the man page for more details.
--timefmt <fmt> strftime-compatible format string
for use with
%T in --format string. #指定事件输出的格式
-c|--csv Print events in CSV format.
-t|--timeout <seconds>
When listening for a single event, time out after
waiting for an event
for <seconds> seconds.
If <seconds> is 0, inotifywait will never time out.
-e|--event <event1> [ -e|--event <event2> ... ]
Listen for specific event(s). If omitted, all events are
listened for. #监控事件
Exit status:
0 - An event you asked to watch for was received.
1 - An event you did not ask to watch for was received
(usually delete_self or unmount), or some error occurred.
2 - The --timeout option was given and no events occurred
in the specified interval of time.
Events:
access file or directory contents were read
modify file or directory contents were written
attrib file or directory attributes changed
close_write file or directory closed, after being opened in
writeable mode
close_nowrite file or directory closed, after being opened in
read-only mode
close file or directory closed, regardless of read/write mode
open file or directory opened
moved_to file or directory moved to watched directory
moved_from file or directory moved from watched directory
move file or directory moved to or from watched directory
create file or directory created within watched directory
delete file or directory deleted within watched directory
delete_self file or directory was deleted
unmount file system containing file or directory unmounted
