Linux系统inotify工具安装配置

inotify主要功能

　　Inotify 是一个 Linux特性，它监控文件系统操作，比如读取、写入和创建。Inotify 反应灵敏，用法非常简单，并且比 cron 任务的繁忙轮询高效得多。学习如何将 inotify 集成到您的应用程序中，并发现一组可用来进一步自动化系统治理的命令行工具。更加详细介绍查看百科介绍

　　Linux内核从2.6.13开始，引入了inotify机制。通过intofity机制，能够对文件系统的变化进行监控，如对文件进行创建、删除、修改等操作，可以及时通知应用程序进行相关事件的处理。这种响应处理机制，避免了频繁的文件轮询任务，提高了任务的处理效率。

inotify安装（操作在centos6.5系统实现）

1. 检查系统内核

[root@node1 ~]# uname -a 
Linux node1 2.6.32-573.el6.x86_64 #1 SMP Thu Jul 23 15:44:03 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

2. 检查是否支持inotify，出现以下结果表明支持

[root@node1 ~]# ls -l /proc/sys/fs/inotify/
total 0
-rw-r--r-- 1 root root 0 Jun 24 01:30 max_queued_events
-rw-r--r-- 1 root root 0 Jun 24 01:30 max_user_instances
-rw-r--r-- 1 root root 0 Jun 24 01:30 max_user_watches

3. 检查是否安装inotify

[root@node1 ~]# rpm -qa inotify-tools
inotify-tools-3.14-1.el6.x86_64

出现以上命令表明已经安装inofity,否则通过以下方式添加安装员，在线安装：

[root@node1 ~]# wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo
[root@node1 ~]# rpm -y install inotify-tools

4. 查看inotifywait命令，确认安装成功

[root@node1 ~]# which inotifywait
/usr/bin/inotifywait

参数详解

[root@node1 ~]# 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. 排除文件或者目录的时候不区分大小写
        -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.后台运行
        -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  安静状态
        -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.指定时间输出的格式
        -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. 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